chore(metrics-summaries): Remove metrics summaries consumer code

[phacops]

Related PR to stop the consumers in prod https://github.com/getsentry/ops/pull/12968.

https://github.com/getsentry/team-ingest/issues/544

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
787	1	786	3

View the top 1 failed tests by shortest run time

tests.consumers.test_schemas::test_all_schemas[case21]

Stack Traces | 0.007s run time

Traceback (most recent call last):
  File ".../tests/consumers/test_schemas.py", line 63, in test_all_schemas
    result = case.processor.process_message(case.example.load(), metadata)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ".../datasets/processors/rust_compat_processor.py", line 26, in process_message
    insert_payload, replacement_payload = self.__process_message(
                                          ^^^^^^^^^^^^^^^^^^^^^^^
rust_snuba.SnubaRustError: processor not found

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