Remove unused CSS file aphront/panel-view.css
Summary:
* `aphront-panel-flush`
** Added in https://we.phorge.it/rP3f11c8a602f0a7567f8a51bc3b1a2dddbd46eec2, usage removed in https://we.phorge.it/rPc05306d746d7e06e3f2a5eb712af89a616abfdc6 by deleting `src/applications/differential/view/DifferentialAddCommentView.php`
* `aphront-panel-preview`
** Added in https://we.phorge.it/rP3f11c8a602f0a7567f8a51bc3b1a2dddbd46eec2, usage removed in https://we.phorge.it/rP6bfb101aff20a1f1f0435178e2de044a945676ba and in https://we.phorge.it/rPc05306d746d7e06e3f2a5eb712af89a616abfdc6 by deleting `src/applications/differential/view/DifferentialAddCommentView.php`
* `aphront-panel-preview-loading-text`
** Added in https://we.phorge.it/rP3f11c8a602f0a7567f8a51bc3b1a2dddbd46eec2, usage removed in https://we.phorge.it/rP6bfb101aff20a1f1f0435178e2de044a945676ba and in https://we.phorge.it/rPc05306d746d7e06e3f2a5eb712af89a616abfdc6 by deleting `src/applications/differential/view/DifferentialAddCommentView.php`
Test Plan: Grep the code for each CSS selector (`grep --exclude="*.css" -R 'some-search-string' .`), also do partial searches, get no results.
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D26007