Update issuable lists: part 1
What does this MR do and why?
Note: this is part 1 of many to get to something sort of like the design in Issue list row re-design (#22482 - closed)
Updates design of issuable lists:
- Truncates branch name and milestone name
- Only show updated_at if it's not the same as created_at
Screenshots or screen recordings
| Before | After | |
|---|---|---|
| Issues |  |
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| Merge requests |  |
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| Epics |  |
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How to set up and validate locally
Look at the following lists:
- Merge requests
- Issues