Form attributes fixed

[zsilbi]

Hello!

• Type: bug fix

In raising this pull request, I confirm the following:

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I have updated the relevant CHANGELOG
• I have created a PR for the documentation about this change

Small description of change:

Form::setAction() fails when called in Form::initialize() because the default attributes are only set, after the initialize() had finished.

Thanks,
zsilbi

[codecov]

Codecov Report

Merging #14421 into 4.0.x will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            4.0.x   #14421   +/-   ##
=======================================
  Coverage   67.63%   67.63%           
=======================================
  Files         478      478           
  Lines      110895   110895           
=======================================
  Hits        75005    75005           
  Misses      35890    35890