Enable Search and Edit menu actions for any panel/plugin

[dalthviz]

...
Perhaps related is that the Search menu items are greyed out, even after the correct behavior is restored. "Replace text" and "Go to line..." should certainly be context dependent (greyed out for IPython Console), but shouldn't "Find text", "Find next", and "Find previous" be selectable for any widget that supports the Search widget?

Originally posted by @mrclary in #22453 (comment)

[dalthviz]

Some other related comments regarding a possible implementation approach: #22453 (comment) #22453 (comment)