Merge request history lists label changes by the same person can clutter the UI

Problem

If the same person makes many label changes to an MR within a short space of time, each label change is listed individually in the activity. In extreme instances there can be so many changes that the label changes visually clutter the history, obscuring more important details.

Example:

Suggested solution

Collapse label changes in the MR activity log so that there is just one entry for all label changes made by the same person within a short period of time, perhaps 1 minute.

The log entry could be similar to the following:

Ahmed added the following labels 23 hours ago

documentation backend frontend UI polish UI text

Ahmed removed the following labels 23 hours ago

~qa OKR priority2