Show loading state when switching tabs in Discussion Notes

[rithviknishad]

Describe the bug
Currently when we switch between tabs in discussion notes, it takes time to reflect the notes of that tab.

Loading animation is not shown when switching to another tab if there are notes in the previous tab.

This could confuse when users don't have reliable internet access.

To Reproduce
Steps to reproduce the behavior:

1. Go to Discussion Notes (popup or dedicated page, both has the issue)
2. Add some notes
3. Switch to another tab
4. See error

Expected behavior
Loading animation should be present when we switch tab.