Fix/234 callback exception

[ibelar]

Fix callback error display when sent by App::caughtException($exception)

The ApiService::OnFailure(response) method will better handle error response when it contains only html, as output by App::caughtException($exception).

• The method now check if property success if part of the response, which is normally the case when using json output with error: {success: false, message: 'error msg'};
• if not then, try to catch body content of the response string, which is normally the case when App::caugthException is returning the error;
• finally simply display the error in a alert box has last resort.

Note: atk4Js.min will need to be recompile.

[codecov-io]

Codecov Report

Merging #239 into develop will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             develop     #239   +/-   ##
==========================================
  Coverage      73.69%   73.69%           
  Complexity      1051     1051           
==========================================
  Files             58       58           
  Lines           2513     2513           
==========================================
  Hits            1852     1852           
  Misses           661      661

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