18px is not a size used for icons often. In these cases it was also inconsistent with most of the UI.
Affected areas:
* `filter_list` - dropdown, filtering repo issues by project
* `filter_actions` - dropdown, mass-editing issues via issue list
* `sidebar/projects` - dropdown in issue view
* `new_form` - dropdown when creating issue. Projects must be enabled in repo
So all areas are dropdowns. I think these were inconsistent because other dropdowns like Reviewers and Milestones use the usual icons of 16px.
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7175
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: 0ko <0ko@noreply.codeberg.org>
Co-committed-by: 0ko <0ko@noreply.codeberg.org>
