fix serialization for sqs http calls

[baermat]

Motivation

When performing API calls for sqs like "ReceiveMessage" directly via HTTP outside the CLI, the response was malformed. It was malformed in general, and had an additional error for json messages. This PR addresses these issues.

Changes

• fixes the json parsing by taking into account the escaping of a potential json dump

TODO

What's left to do:

• clarify if the asymmetry between the marker conversions has a reason. It seems odd that the code goes to great lengths explaining the reason for all the conversion, only to have these two ways differ -> not doing this results in strange conversion errors for \r on non-json messages.
• while tackling this, I found another bug: the response for ReceiveMessage is potentially further malformed. A usual cli call returns {Messages:[{<msg_1>}, {<msg_2>}, ...]} but we return {Message:{<msg_1>}} if there is one message, and {Message:[{<msg_1>}, {<msg_2>}, ...]} if there are more than one (note the missing plural s of Message). AWS' response is also different with a "direct" http call, but it is only the case that is different ("Messages" vs "messages"). How to proceed here? It seems to be an error in the automatic response creation of LS

[github-actions]

S3 Image Test Results (AMD64 / ARM64)

  2 files  ±0    2 suites  ±0   3m 21s ⏱️ +20s
398 tests ±0  346 ✅ ±0   52 💤 ±0  0 ❌ ±0 
796 runs  ±0  692 ✅ ±0  104 💤 ±0  0 ❌ ±0 

Results for commit 38a9aad. ± Comparison against base commit 0f7d49f.

♻️ This comment has been updated with latest results.

[github-actions]

LocalStack Community integration with Pro

    2 files  ±0      2 suites  ±0   1h 36m 56s ⏱️ - 1m 52s
2 928 tests +2  2 634 ✅ ±0  294 💤 +2  0 ❌ ±0 
2 930 runs  +2  2 634 ✅ ±0  296 💤 +2  0 ❌ ±0 

Results for commit 38a9aad. ± Comparison against base commit 0f7d49f.

This pull request removes 5 and adds 7 tests. Note that renamed tests count towards both.

tests.aws.services.events.test_events.TestEvents ‑ test_event_pattern
tests.aws.services.events.test_events.TestEvents ‑ test_put_event_without_source
tests.aws.services.events.test_events.TestEvents ‑ test_put_events_with_nested_event_pattern
tests.aws.services.events.test_events.TestEvents ‑ test_put_events_with_values_in_array
tests.aws.services.events.test_events.TestEvents ‑ test_put_target_id_validation

tests.aws.services.events.test_event_patterns ‑ test_event_pattern_source
tests.aws.services.events.test_events.TestEventPattern ‑ test_put_events_pattern_nested
tests.aws.services.events.test_events.TestEventPattern ‑ test_put_events_pattern_with_values_in_array
tests.aws.services.events.test_events.TestEventTarget ‑ test_put_target_id_validation
tests.aws.services.events.test_events.TestEvents ‑ test_put_events_without_source
tests.aws.services.sqs.test_sqs.TestSqsProvider ‑ test_marker_serialization_json_protocol["{\\"foo\\": \\"ba\\rr\\"}"]
tests.aws.services.sqs.test_sqs.TestSqsProvider ‑ test_marker_serialization_json_protocol[{"foo": "ba\rr", "foo2": "ba"r""}]

This pull request skips 1 test.

tests.aws.services.events.test_events.TestEvents ‑ test_put_event_without_detail

♻️ This comment has been updated with latest results.

[alexrashed]

Whoof, that must have been terrible to pin down! Really great catch! Thanks a lot for tackling this! 🦸🏽
The implementation looks good (as good as it can be on my initial hacky solution), the AWS validated test is great to avoid a regression in the future, and to have a kick-start when tackling the other issue you detected. 🚀

[thrau]

Tested and works great, also via the dev endpoint. Thanks @baermat, nice job tracking this down! 💯