fix: datepicker focus outline shouldnt be cut off

[rBortnikas]

Fixes datepicker’s day focus outline cut off issue.

Description

Currently, day's focus outline is partly covered by the following day’s cell. The images and the recording explain this better. This fix makes the datepicker look a little more polished.

Before

After

https://user-images.githubusercontent.com/17082436/191592924-67021dce-bdb8-4948-b5d1-c592fc22c402.mp4

Scope

Patch: Bug Fix

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[chasestarr]

Thank you for this PR. We will need to figure out a solution that does not use z-index. Please use another method for creating a stacking context. We almost never use z-index in base web