Fix GCE tests in CI

[yadudoc]

Description

The GCE testing CI action was not setup to install parsl from the local repo but was installing the Parsl version pinned to globus-compute-endpoint. With the latest parsl not installed, running tests against the endpoint would trigger errors as @benclifford mentioned here:

E                ModuleNotFoundError: No module named 'parsl.tests.test_python_apps.test_exception'

Type of change

• Bug fix

[benclifford]

this is going to break in the same but different way when the Parsl API or internal not-API changes in a way that the GC endpoint hasn't tracked yet, right? (as an example, JobStatusPoller going away as an independent entity and merging into BlockProviderExecutor would be a likely thing to happen in the next two years)

[yadudoc]

@benclifford Yes, that is likely to happen when either Parsl or GC makes changes that are incompatible. The other option is to make breaking changes in Parsl get that released and have GC update the parsl pin to the latest. This seems far more tedious than the current solution here. Or, we drop support for GC entirely.

[benclifford]

If these tests are going to be subject to continuous awkward catchup games from the GC team, I guess thats fine although I would prefer it not be that way. But probably the GC team should be reviewing its own PRs for that, rather than me.

[khk-globus]

Like BenC, I'm not overly pleased with this current state of affairs, but I don't have an immediate better alternative either. I'm approving this now to "move on," but I expect that we will causally revisit this entire plugin at some point.