Rework BeakerAgentQuery component so it does not display the input box when it cannot be used

[mattprintz]

Currently, the entire time an agent is working on an issue, the query cell remains.
This holds for both regular react loop requests and workflows.

Allowing a user to enter and submit a new query either does not work or causes undefined behavior.
As such, we should disable, hide, or replace the query text input element and submit button.

Options:

• Just disable text box and button when not able to be used
• Replace input box with the Agent Activity Indicator component (thoughts, etc)
• Collapse input area so it doesn't take up screen real-estate