Terminate Field Slip Status Requests

[JoeCohen]

• Fixes how the js controller stops sending GET requests when the job is done.
• Contains only one commit, authored by @Nimmo, (cherry picked from commit 70155d9) and effectively moved from InatImportJobTracker auto updates #2702 so that it can be considered separately.

[mo-nathan]

Looks reasonable to me. Wonder if we have any way to test it.

[JoeCohen]

@nimmolo: Like @mo-nathan said here, I also don't understand what this fixes in Field Slips.
In main it stops sending GET "/field_slip_job_trackers" requests as soon as the Field Slip pdf is complete.

[nimmolo]

There must be something different about the Stimulus that I didn't notice when comparing to iNatImport Stimulus.

Oh i know. It's the difference between update and replace.

[nimmolo]

Actually I do think this PR is still worth it, for two reasons.

• It removes an inaccurate comment of mine about not calling this class methods within setInterval
• It contains an improved code pattern (in the sense of usable in future templates) than the current version.

Currently the "pdf finished" code clears the interval and removes the name of the controller from the "data-stimulus" attribute, but does not actually disconnect the controller; that's handled in the disconnect function. I think the "pdf finished" code should simply clearInterval, this will create less confusion for future coders, including me!

[JoeCohen]

@nimmolo.

• Could you have another look at this. When I tested it manually, the tracker sent GET requests forever. And it appears (but probably isn't the case) that the job never finishes. (Perhaps I messed up the branch.)

• Is there a way -- other than a system test -- to test this?