Using press to activate the Tweak tool doesn't work well when used a
fallback tool as the drag event is often used by the current tool -
making it impossible not to select when dragging (unless the fallback
tool is disabled entirely).
Resolve this by using CLICK events when the Tweak tool is used as a
fallback.
Even though this avoids the crash, check for null-pointer de-reference
since changes to the key-map shouldn't cause operators to crash.
Note that the ability for operators to access a gizmo before it's fully
initialized is a more general problem that should be addressed, but out
of scope for a bug-fix.
Reviewed By: zeddb, JulienKaspar, Severin
Maniphest Tasks: T95591
Ref D14231
0e51defcf4