fix: notification tray height issues

[sundasnoreen12]

INF-1052

Description

Fixed following issues.

1. The notifications tray looks to be overlapping the NAV
2. When I scroll down the page I see a gap at the top, showing other LMS content:
3. There’s also a gap on the right, showing LMS content:

Screenshots

[codecov-commenter]

Codecov Report

Merging #479 (f0c3681) into master (903802d) will increase coverage by 0.69%.
Report is 8 commits behind head on master.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##           master     #479      +/-   ##
==========================================
+ Coverage   76.47%   77.17%   +0.69%     
==========================================
  Files          48       48              
  Lines         744      736       -8     
  Branches      134      133       -1     
==========================================
- Hits          569      568       -1     
+ Misses        172      165       -7     
  Partials        3        3              

Files	Coverage Δ
src/Notifications/index.jsx	82.60% <83.33%> (+10.38%)	⬆️

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