Fix grpc tests when running from cmd-line/eachdist script

[mariojonke]

Description

When running the grpc tests from the command line with pytest instrumentation/opentelemetry-instrumentation-grpc/tests or python scripts/eachdist.py test the 2nd test in the TestClientProto test case was failing with:

instrumentation/opentelemetry-instrumentation-grpc/tests/test_client_interceptor.py:200: in _verify_error_records
    ("status_code", grpc.StatusCode.INVALID_ARGUMENT),
E   AssertionError: Tuples differ: (('me[65 chars]code', <StatusCode.UNAVAILABLE: (14, 'unavailable')>)) != (('me[65 chars]code', <StatusCode.INVALID_ARGUMENT: (3, 'invalid argument')>))
E   
E   First differing element 1:
E   ('status_code', <StatusCode.UNAVAILABLE: (14, 'unavailable')>)
E   ('status_code', <StatusCode.INVALID_ARGUMENT: (3, 'invalid argument')>)
E   
E     (('method', '/GRPCTestServer/BidirectionalStreamingMethod'),
E   -  ('status_code', <StatusCode.UNAVAILABLE: (14, 'unavailable')>))
E   ?                              ^ -   ^ ^^    ^^   ^ -   ^ ^^
E   
E   +  ('status_code', <StatusCode.INVALID_ARGUMENT: (3, 'invalid argument')>))
E   ?                              ^   + ^^ ^^^^ ++ 

Looks like the problem is a leftover connection from the previous test due to the channel not being properly closed on test teardown. The current test then fails to connect to the test server which results in StatusCode.UNAVAILABLE.

For tox tests this was already addressed in #974 by pinning the gprc version to 1.30

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Run pytest instrumentation/opentelemetry-instrumentation-grpc/tests without and with closing the channel.

[codeboten]

Change looks good, just a non-blocking question

[codeboten]

Just checking, this isn't required for the test to pass correct?

[mariojonke]

No it is not required. The tests work also without this change.
Since #974 / #975 fixed the tox tests this is just restoring the requirements to the previous state since it now also works with the lower version.

[codeboten]

Sounds good 👍