PR: Make the list view of the file switcher look active at all times.

[jnsebgosselin]

Description of Changes

• Wrote at least one-line docstrings (for any new functions)
• Included a screenshot or animation (if affecting the UI, see Licecap)

Trick the html delegate that is used in the list view of the file switcher into thinking that it is active at all times, even if strictly speaking it is not.

See #10682 for more details.

Issue(s) Resolved

Fixes item number 2 in #10682

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: Jean-Sébastien Gosselin

[goanpeca]

@jnsebgosselin could you add an issue on Qdarkstyle to add a difference between active and not active items?

[jnsebgosselin]

@jnsebgosselin could you add an issue on Qdarkstyle to add a difference between active and not active items?

sure, I will do it.

Edit: The aforementioned qdarkstyle issue can be found at ColinDuquesnoy/QDarkStyleSheet#209

[goanpeca]

Tested on Mac, works as expected