[FEATURE] Improve and/or clarify Server payload in relation to bound witness testing.

[pllearns]

Is your feature request related to a problem? Please describe.
Although we can update the payload string to test an interaction with, where in the UI is it clear on how to use?

Describe the solution you'd like
We should see an additional heuristic displayed in the bound witness block response with the payload test string to confirm further, or remove the payload string textarea and button altogether.

Describe alternatives you've considered
Removing the payload feature or replacing with a selectable area with heuristics to test with. Including customizable fields.