PR: Fix for search/find close button error (Variable Explorer)

[dalthviz]

Description of Changes

• Wrote at least one-line docstrings (for any new functions)
• Added unit test(s) covering the changes (if testable)

• Included a screenshot or animation (if affecting the UI, see Licecap)

Multiple instances of the finder (close button + line edit) were being created. The main problem was not related to creating the whole finder element multiple times but the close button (which was like declaring the same action multiple times).

Now only one instance of the finder is created.

TODO:

• How to keep text input and the visibility of the search bar for the different Name Space Browser (i.e one could have the search visible while another one could have it invisible, also one could have some text in it while the other is blank)

Preview

Issue(s) Resolved

Fixes #15010

Affirmation

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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: dalthviz

[pep8speaks]

Hello @dalthviz! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-03-28 19:36:38 UTC

[ccordoba12]

Thanks a lot @dalthviz for your help with this!

[ccordoba12]

Note: I took the opportunity to fix a bug I found while testing this: the variable explorer options were not applied to all namespace browsers, just to the visible one.