[Feedback] Do not minify feedback issue body

[jiasli]

(Requires #17324)

Resolve #16386

Context

az feedback opens an GitHub issue by filling the body query parameter. (See About automation for issues and pull requests with query parameters)

https://github.com/azure/azure-cli/issues/new?body={}

Due to the URL length limitation on some legacy web browsers like IE, CLI minifies the issue body (especially call stack) to fit the URL length into the limitation:

azure-cli/src/azure-cli/azure/cli/command_modules/feedback/custom.py

Line 34 in e3ac647

_MAX_URL_LENGTH = 2035

This sometimes truncates the call stack has caused us many problems while troubleshooting (#16386).

Modern browsers are already accepting URL length exceeding the old limitation (https://stackoverflow.com/a/417184), so the motivation to minify the error_string is less reasonable.

The minification process is also very error prone (#17301).

Change

This PR

1. removes the minification logic
2. tells the user to manually open an issue if the URL exceeds the browser or GitHub's limitation

Testing Guide

1. Place raise Exception after

   azure-cli/src/azure-cli-core/azure/cli/core/adal_authentication.py

   Line 118 in f7fc070

   def signed_session(self, session=None): # pylint: disable=arguments-differ

2. Run az group list to trigger a very long error stack
3. Run az feedback

[yonzhan]

Feedback