* [wip]fix: disable fill and gradient tools on bmp images
- aims to fix#1161
* [wip]fix: disable gradient tool for bmp images
* fix: disable gradient tool for bitmap images
- fixes https://github.com/GraphiteEditor/Graphite/issues/1161
* [wip]fix: disable menu bar elements if no open document
* [WIP]feat: render certain menubar elements if document is open
* fix: conditional menu bar rendering fixes
- update menu bar on certain document actions
- fix menu bar order on rendering all elements
* refactor: change conditional menu elements property
- use existing 'disabled' property
* feat: render menu dropdown items conditionally
* fix: revert formatter whitespace changes
* refactor: improve variable naming and message usage
- name menu bar bool flag better
- use SendLayout message and remove unneeded calls