Change max task reason to 1024 characters

[angelcar]

Summary

Trimming task reason to a max of 1024 characters as per Back-end model.

Implementation details

• Renamed existing constant that defines a max reason of 255 characters to be container-specific
• Added new constant to limit max reason for the task, as opposed to container's reason
• Reusing existing string trimming function

Testing

UTs
Functional Tests

New tests cover the changes: yes

Description for the changelog

• Enhancement - Trimming task reason to a max of 1024 characters as per Back-end model.

Licensing

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.