[Airflow-5144] confirmation dialogue on delete

[h5chauhan]

As per pallets-eco/flask-admin#1789 the deleted button did not show a confirmation alert. This issue has
been fixed in newer version of flask-admin

Make sure you have checked all steps below.

Jira

• My PR addresses the following AIRFLOW-5144 issues and references them in the PR title.

Description

• Here are some details about my PR, including screenshots of any UI changes:
  Confirmation dialogue on click of delete was not showing up due to Delete confirmation no longer shows in list view pallets-eco/flask-admin#1789 since the fix is now merged this PR upgrades the flask-admin version. I have tested creating and deleting variables and connections on the UI. A screenshot with the confirmation dialogue appearing on delete is attached.

Tests

• My PR add not need testing for this extremely good reason: AFAIK no unit tests exists for UI

Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. The subject is separated from the body by a blank line

Documentation

• This is restoring the functionality of confirmation dialogue before deleting a variable or connection.

[codecov-io]

Codecov Report

Merging #6745 into v1-10-test will increase coverage by <.01%.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           v1-10-test    #6745      +/-   ##
==============================================
+ Coverage       79.69%   79.69%   +<.01%     
==============================================
  Files             518      518              
  Lines           35300    35300              
==============================================
+ Hits            28132    28134       +2     
+ Misses           7168     7166       -2

Impacted Files	Coverage Δ
airflow/utils/dag_processing.py	58.86% <0%> (+0.32%)	⬆️

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