Fix the dpad navigation & dialog styles

[Rawa]

• Fixes DPAD navigation in dialogs
• Aligns dialog designs to use Alert Dialog
• Introduces mullvadDarkTextFieldColors
• Fixes textfield width on wide devices

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This change is 

[linear]

DROID-401 Investigate and fix the DPAD navigation bug on Alert Dialog

There needs double up/down DPAD clicks on alert dialog to reach stuff for the first time.

[Pururun]

Tested it and it works much better. However when I try with dpad on an emulator there is inconsistent behaviour when comparing the input field of redeem voucher and all other dialogues. Is this intended and can you see this different behaviour on the TV?

Reviewed 10 of 10 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[Rawa]

A great remark, there was a box surrounding the RedeemVoucherDialog, does it work better now? :)

Reviewable status: 1 of 10 files reviewed, all discussions resolved (waiting on @Pururun)

[Pururun]

Works great. :)

Reviewed 4 of 4 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[sabercodic]

Reviewed all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved