Dynamic assignment batches

[schuyler1d]

Fixes https://github.com/MoveOnOrg/Spoke/issues/1533

Description

Changes Dynamic Assignment

TODO:

• extensible changes to AssignmentSummary (on the todos page) from texter-sideboxes
• extensible changes to assignment.hasUnassignedContactsForTexter so a choice for when/who can request another batch (e.g. vetted texters, or after replies are finshed, etc)
• change/add tests

Checklist:

• I have manually tested my changes on desktop and mobile
• The test suite passes locally with my changes
• If my change is a UI change, I have attached a screenshot to the description section of this pull request
• [NO] My change is 300 lines of code or less, or has a documented reason in the description why it’s longer
• I have made any necessary changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• My PR is labeled [WIP] if it is in progress

[hiemanshu]

@schuyler1d One change that was made after we open sourced the patches was to change the findNewCampaignContact mutation to only reassign when message_status is needsMessage, otherwise it would reassign replies, and other side effects.

Here: https://github.com/MoveOnOrg/Spoke/blob/main/src/server/api/mutations/findNewCampaignContact.js#L70