Fixes one failure in #8942 which caught a real issue: clicks at various panels were triggering many handlers at once, often unexpectedly - for example quick clicking at breadcrumbs (and automatic tests always click fast) we could also trigger getting out the current node.
Therefore, I added `stopPropagation` for all mouse events on "panel" level + where I think the event should be considered "handled" and no longer bother anyone. Also, to unify things, most actions are for `click` event.
Additionally I spotted and fixed some issues:
* When "clicking-off" Component Browser, it creates new node only if anything was actually typed in (no more dangling `operatorX.` nodes)
* Filtering now works for operators
* When, after opening CB with source node, user starts typing operator, we replace dot with space
* Fixed our shortcut handler, so it works properly with `click` event.
* Fixed problems with defocusing input in CB when clicking at links.
# Important Notes
I removed `PointerMain` binding for deselectAll, because it was triggered every time did the area selection.
Part of #8518Closes#8822
The drop downs were missing, because WidgetFunction had a higher score than them and took precedence. The fix was to adjust scores, so drop down is before both argument name and function. Generally, any widget expecting to "overlap" existing code (and possibly further widgets) should go before WidgetFunction.
# Important Notes
* Extended mockExpressionUpdate to accept a subexpression of a node. Also, I removed it from GraphDb - I want this function to have as little impact on app code as possible.
Related to https://github.com/enso-org/enso/issues/8518
These tests already caught one regression in nav breadcrumbs: https://github.com/enso-org/enso/issues/8756
It also provides API for mocking expression updates for arbitrary nodes on the screen. The implementation is a bit convoluted and includes setting a callback on `window`, but it looks like the only possible solution given our architecture and playwright restrictions.
