fix: ensure focused month is visible when receiving focus (#3219) (CP: 14.0)

[vursen]

Description

A cherry-pick of vaadin/web-components#3219.

Fixes vaadin/web-components#1892.

Type of change

• Bugfix

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

[CLAassistant]

All committers have signed the CLA.

[vursen]

Some newly added unit tests are failing in IE11. Debugging showed that clientHeight of the month scroller in IE11 is different from other browsers. It may have something to do with the flex layout:

https://stackoverflow.com/questions/58175011/ie11-has-different-clientwidth-and-clientheight-than-all-other-browsers

[yuriy-fix]

Closing as the original fix is not aiming critical issue. No need to be backported.

[vursen]

Closing as the original fix is not aiming critical issue. No need to be backported.

Let me not agree. Were the following factors considered before closing?

• The original issue was reported for V14.
• The scrolling error accumulates in certain conditions so that at some point you may end up navigating completely outside the visible area without this fix.

[vursen]

For some reason, Gemini demanded to update the week-number screenshot even though there is no visible difference: 53d66d2. At least, I couldn't spot any difference whatever angle I looked at it from 🤔

I assume, however, there can be a very subtle difference in scroll position that can be a result of the revealDate method that was changed in this PR.

[tomivirkki]

Works well, also on IE11