Firewall improvement

[ruudboon]

Hello!

• Type: bug fix
• Link to issue:[BUG]: Input type not checked in Phalcon\Events\Event #14449

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:

Thanks

[codecov]

Codecov Report

Merging #14450 into 4.0.x will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##            4.0.x   #14450      +/-   ##
==========================================
- Coverage   67.71%    67.7%   -0.01%     
==========================================
  Files         482      482              
  Lines      111207   111222      +15     
==========================================
+ Hits        75304    75308       +4     
- Misses      35903    35914      +11