fix(ui5-calendar): render the correct length of day names

[tsanislavgatev]

fixes: #7831

[ilhan007]

Noticed that the issue authors need a downport to 1.14

Do the following: after merging the fix into the main branch:

• Update your local "main" branch to get the fix

• checkout latest 1.14.5 tag as a local branch with name release-1.14.6
  git checkout -b release-1.14.6 tags/v1.14.5

• cherry-pick the fix into the newly created local branch (e.g. release-1.14.6)
  git cherry-pick commitSha

• test that everything works as expected locally (1.14 is 5 months old, explore the code could be that the fix should be in different place, method , etc.)

• push your local branch to the remote
  git push origin release-1.14.6

[tsanislavgatev]

Push to release-1.14.16 was performed.