fix(datepicker): update subscriptions of datepicker-inline and daterangepicker-inline

[JoschuaSchneider]

Context

Both datepicker-inline and daterangepicker-inline don't update their subscriptions to the datepicker instance after calling setConfig.
This causes the datepicker to not fire bsValueChanges after one of the datepickers inputs have changed.

Changes

• Introduce updateSubscriptions method to unsubscribe from previous subscriptions and to create new subscriptions on new _datepickerRef.instance
• Reduce calls to setConfig by introducing a shouldSetConfig flag, thereby batching complex updates together

Closes #5888 where EventEmitter does not fire after Input changes

PR Checklist

Before creating new PR, please take a look at checklist below to make sure that you've done everything that needs to be done before we can merge it.

• read and followed the CONTRIBUTING.md guide.
• built and tested the changes locally.
• added/updated tests.
• added/updated API documentation.
• added/updated demos.

[codecov]

Codecov Report

Merging #6201 (b22cff9) into development (e3b2d7d) will decrease coverage by 0.04%.
The diff coverage is 36.36%.

❗ Current head b22cff9 differs from pull request most recent head c333dc7. Consider uploading reports for the commit c333dc7 to get more accurate results

@@               Coverage Diff               @@
##           development    #6201      +/-   ##
===============================================
- Coverage        77.52%   77.47%   -0.05%     
===============================================
  Files              302      302              
  Lines            10549    10566      +17     
  Branches          2583     2587       +4     
===============================================
+ Hits              8178     8186       +8     
- Misses            2361     2370       +9     
  Partials            10       10              

Impacted Files	Coverage Δ
src/datepicker/bs-datepicker-inline.component.ts	53.33% <36.36%> (+0.24%)	⬆️
.../datepicker/bs-daterangepicker-inline.component.ts	59.30% <36.36%> (+0.32%)	⬆️
src/chronos/i18n/pl.ts	81.66% <0.00%> (-3.34%)	⬇️
src/chronos/i18n/cs.ts	87.64% <0.00%> (ø)
src/chronos/i18n/sk.ts	85.13% <0.00%> (ø)

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[cypress]

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Test summary

818 • 12 • 14 • 0

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Run details

Project	ngx-bootstrap
Status	Failed
Commit	b22cff9 ℹ️
Started	Aug 20, 2021 10:24 AM
Ended	Aug 20, 2021 10:37 AM
Duration	13:05 💡
OS	Linux Ubuntu - 20.04
Browser	Electron 87

View run in Cypress Dashboard ➡️

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Failures

	modals_service_page_spec.ts		3
1	Modals demo page testing suite: Service examples > Component modals with interceptor > when user clicks on "Close" button, triggers the interceptor and doesn't close the modal
2	Modals demo page testing suite: Service examples > Component modals with interceptor > when user clicks on "Yes" button, closes the modal
3	Modals demo page testing suite: Service examples > Component modals with interceptor > when user clicks on "No" button, doesn't close the modal
	carousel_page_spec.ts		5
1	Carousel page testing suite > Slide changed event > example contains slides, indicators, left and right controls and "Slide has been switched: 0"
2	Carousel page testing suite > Slide changed event > when user click on left arrow - info changed to "Slide has been switched: 2"
3	Carousel page testing suite > Slide changed event > when user click on left arrow again - info changed to "Slide has been switched: 1"
4	Carousel page testing suite > Slide changed event > when user click on right arrow - info changed to "Slide has been switched: 1"
5	Carousel page testing suite > Slide changed event > when user click on right arrow again - info changed to "Slide has been switched: 2"
	pagination_page_spec.ts		1
1	Pagination demo page testing suite > Pager > example contains: 7 pages, Next - active, Previous - active, 4th page active
	buttons_page_spec.ts		1
1	Buttons page testing suite > Buttons Custom checkbox value example > when user clicks on it, btn become inactive and custom checkbox value should be "0"
This comment includes only the first 10 test failures. See all 12 failures in the Cypress Dashboard.

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[rfrcarvalho]

Does anyone have an ETA on this PR being approved and merged? This is currently blocking my app from being deployed as the inline calendar has these bugs.

[JoschuaSchneider]

Hey, I would love to reduce the amount of work you have to deal with on this PR.
Would resolving the conflicts with the current development branch do any good?