This makes it less cumbersome to search for channels by
selecting the textbox above the channel list. It feels nicer
to use and has the niceties that come from using that textbox,
like searching per keystroke, compared to the old pop-up method.
This works similarly to how pressing ctrl+f in the text editor
works by having the channel region pop-up and then
select the channel filter textbox during the draw method, if
a flag is set.
This also renames the operator for ctrl + f animation channels to reflect the new function and changes the keymap.
Videos to show difference
Old
New