Audit/rewrite `PNT30` flake8 lint failures to achieve more concurrency

[huonw]

Is your feature request related to a problem? Please describe.

In #18303, a new flake8 rule is added that flags constructs like [await Get(...) for ... in ...]. If these are embarrassingly parallel (i.e. no dependencies between iterations), they should be rewritten to use MultiGet: for instance, await MultiGet(Get(...) for ... in ...).

That PR added noqa: PNT30: requires triage annotations to many instances of this, rather than fix them. This issue is about going through and either fixing them or making the annotation more specific.

Embarrassingly parallel:

• src/python/paths/backend/go/goals/debug_goals.py
• src/python/paths/backend/go/goals/generate.py
• src/python/paths/backend/go/util_rules/cgo.py
• src/python/paths/backend/go/util_rules/go_bootstrap.py
• src/python/paths/backend/go/util_rules/goroot.py
• src/python/paths/backend/helm/util_rules/post_renderer.py
• src/python/paths/backend/python/framework/django/detect_apps.py
• src/python/paths/bsp/util_rules/targets.py
• src/python/paths/core/goals/deploy.py
• src/python/paths/core/goals/update_build_files.py Triage some noqa: PNT30 await-in-loops #18831
• src/python/paths/engine/internals/build_files.py Triage some noqa: PNT30 await-in-loops #18831
• src/python/paths/engine/internals/dep_rules.py
• src/python/paths/jvm/goals/lockfile.py
• src/python/paths/source/source_root.py Triage some noqa: PNT30 await-in-loops #18831

Embarrassingly parallel, except there's an early return, so just moving all invocations to a MultiGet might result in more work total.

• src/python/paths/backend/cc/util_rules/toolchain.py
• src/python/paths/backend/python/goals/setup_py.py
• src/python/paths/core/subsystems/python_bootstrap.py

Describe the solution you'd like
For each of the files above, rewrite the loops that call await Get(...) internally to use MultiGet.

Describe alternatives you've considered
N/A
Additional context
N/A

[kaos]

This one was never an issue, as there is a return at the end of the for-body it effectively works as an if-then block.

pants/src/python/pants/engine/internals/dep_rules.py

Lines 162 to 168 in eb175f5

	for request_type in request_types:
	impl = await Get( # noqa: PNT30: this for loop will never process more than a single iteration.
	BuildFileDependencyRulesImplementation,
	BuildFileDependencyRulesImplementationRequest,
	request_type(),
	)
	return MaybeBuildFileDependencyRulesImplementation(impl.build_file_dependency_rules_class)

Opted to fix the noqa text in #18112 to save on CI cycles.