Consistently display script icons for nodes in connect dialog's scene tree editor

[stephen-berry]

#92513 requested to be able to view script icons with/without the ConnectDialog's advanced tab enabled for better context when selecting signals.

The change made was simple, with the biggest change involving the use of 'connecting_signal' boolean to ensure all script icons are displayed (custom or otherwise) when the connect dialog scene tree is open.
Before this change, all icon additions were made under the connect_to_script_mode. When Advanced is enabled, the connect_to_script_mode is set to false, which results in never adding the script buttons to the scene tree editor.

The fix should be low-risk because the icons are only added during connect dialog scene tree's. I would have added tests, but I noticed there are currently no test files under editor/ (and this being my first ticket, I wasn't sure how to proceed with the tests).

The 'before change' video (linked in the original ticket) displays the issue, and below I have the 'after change' result of both advanced off/on.

Advanced off:

Advanced on:

Bugsquad edit:

• Fixes Connection dialog does not show script icon in advanced mode #92513.

[akien-mga]

Looks good! Could you squash the commits? See PR workflow for instructions.

[stephen-berry]

I will squash them as soon as possible (away from PC til sunday :0) thank you! :)

[stephen-berry]

After interactive rebasing, I noticed I didn't see my 2 review commits from here. I added them and amended them as a commit to previous. I hope this is okay, and feel free to let me know if there's something else I should have done :) sorry for any inconvenience (and thank you for reviewing!)

[akien-mga]

After interactive rebasing, I noticed I didn't see my 2 review commits from here. I added them and amended them as a commit to previous.

Yes what you did looks correct. We like that simple PRs have a single commit, so fixups following PR review should be amended into the original commit to keep it as a single commit.

I pushed another rebase of your branch as there was a temporary CI failure due to GitHub Actions changes, unrelated to this PR.

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉