Enhancement: fix issue card sizing when filtering

[TobyCyan]

Summary:

Fixes #484

Type of change:

• ✨ New Feature/ Enhancement

Changes Made:

• Made issue cards have a consistent sizing by enforcing a fixed width (300px) (Other scale units would break the margin and padding consistency between issue-tables).
• Made its child elements stretch to 100% width.

Screenshots:

Issue-484-Demo.mp4

Proposed Commit Message:

Fix issue card sizing

The issue cards have inconsistent sizes during filtering.

The lack of size consistency does not look very good
to the user viewing a huge number of issues.

Let's,
* fix the width of the parent issue-table.
* make the issue cards cover 100% of the parent's width.

This should give more control over the desired 
column width for each issue-table and improve
size consistency for better visual appeal.

Checklist:

• I have tested my changes thoroughly.
• I have created tests for any new code files created in this PR or provided a link to a issue/PR that addresses this.
• I have added or modified code comments to improve code readability where necessary.
• I have updated the project's documentation as necessary.

[NorbertLoh]

I quite like this change as it makes everything more consistent.
Could we look into the alignment of the Unassigned? Looks a little off especially with more space now. Otherwise LGTM!

[TobyCyan]

@NorbertLoh thank you for the suggestion! Will look into it!

[TobyCyan]

@NorbertLoh I've removed the assignee avatar div which caused the extra spacing for Unassigned, here is how it looks next to another assignee container!

Please let me know if you would like me to reduce/remove the left padding for unassigned (currently 10px).

[bipplane]

this is amazing (the card sizes have been fixed)

[NorbertLoh]

LGTM!

[NorbertLoh]

Perhaps your git commit message subject could match the other PRs just for consistency! Otherwise LGTM!