fix(progress-indicator): accept 0 as a valid value

[gafortuno]

What I did

1. Updated the condition in removing the value attribute.
2. When the value is set to 0, currently, without this fix, the value is being removed because the condition is !this.value || typeof this.value !== 'number' => !0 is equal to true that's why the progress bar value is being removed (this.removeAttribute('value'))
3. I updated the condition to check if the value is 0, it will be accepted and the value attribute will not be removed.
4. I also added and updated the unit test. The current unit test on setting the value of the value attribute to an empty string will fail because according to this documentation, on the convertion for Number (attribute to property) If the element has the corresponding attribute, set the property to Number(attributeValue). So, if the value is set to '', it will be Number('') which is equal to 0.

[changeset-bot]

🦋 Changeset detected

Latest commit: 92e286e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@lion/ui	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[CLAassistant]

All committers have signed the CLA.

[gafortuno]

Before the fix:

If value is set to 0, it's taking the whole progress:

width is not being set properly because the value attribute is removed and it is considered indeterminate

value becomes null

After the fix:

[gerjanvangeest]

Looks good to me, can you add a changeset npm run changeset, to add the change to the changelog?

[gafortuno]

Added changeset thanks @gerjanvangeest