fixed ui consistency in sidebar

[Shree-444]

PR Fixes:

• The bottom border of the sidebar toggle button was misaligned with the top navbar's horizontal border.
• Made changes to the padding, thus fixing the alignment.

Resolves #1864

Fixed alignment

Checklist before requesting a review

• [x] I have performed a self-review of my code
• [x] I assure there is no similar/duplicate pull request regarding same issue