feat(static-html): Make the descriptions of issues more compact

[fviernau]

Only show the Issue.message, but stop showing Issue.timestamp and Issue.severity, to make the representation more compact and to align with the WebApp report. Note that the timestamp is rarely relevant and the severity is represented by a dedicated styling anyway.

[sschuberth]

I was a bit hesitant about the rationale at first, as we seem to have tickets that go a little bit into the other direction for the web-app report (like https://github.com/oss-review-toolkit/ort/issues/4041, https://github.com/oss-review-toolkit/ort/issues/8211), but these tickets do not refer to the issue time and severity specifically, so I believe this change is ok.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 67.92%. Comparing base (6ae4429) to head (e3d0c45). Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8668   +/-   ##
=========================================
  Coverage     67.92%   67.92%           
  Complexity     1005     1005           
=========================================
  Files           244      244           
  Lines          7772     7772           
  Branches        876      876           
=========================================
  Hits           5279     5279           
  Misses         2110     2110           
  Partials        383      383           

Flag	Coverage Δ
funTest-non-docker	34.79% <ø> (ø)
test	37.84% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.