[UX] TestPlan - Add tag longer than 255 characters

[Prome88]

Description of problem

Version or commit hash (if applicable)

v8.8

Steps to Reproduce

1. Open test plan page
2. Input string longer than 255 characters into Tags input field
3. Click on + icon

Actual results

Expected results

Instead of internal server error show user friendly warning that tags are at most 255 characters long or maybe lock the input field to maximum of 255 characters.

Additional info (Python traceback, logs, etc.)