Fix S3 CRT async request lifetime

[FranciscoMaxwell]

Issue #, if available:
Fixes #3881

Description of changes:
This updates the S3 CRT async callback state to keep the original service request alive until the CRT shutdown callback runs.

Previously, CrtRequestCallbackUserData stored originalRequest as a raw pointer to the request reference passed into CopyObjectAsync, GetObjectAsync, and PutObjectAsync. Those async methods can return before the CRT callbacks finish, leaving headers/body/progress/shutdown callbacks with a dangling pointer when they access GetContinueRequestHandler() or pass the typed request to the user response handler.

The callback data now owns a shared_ptr copy of the request. InitCommonCrtRequestOption receives and stores that shared_ptr, and the shutdown callbacks use the owned request when invoking the user handler.

Check all that applies:

• Did a review by yourself.
• Added proper tests to cover this PR. (No new unit test was added; this lifetime issue depends on the async CRT request lifecycle. I verified the affected target builds successfully.)
• Checked if this PR is a breaking (APIs have been changed) change.
• Checked if this PR will not introduce cross-platform inconsistent behavior.
• Checked if this PR would require a ReadMe/Wiki update.

Check which platforms you have built SDK on to verify the correctness of this PR.

• Linux
• Windows
• Android
• MacOS
• IOS
• Other Platforms

Testing:

• git diff --check
• cmake -S . -B build-s3crt -DBUILD_ONLY=s3-crt -DENABLE_TESTING=OFF -DAUTORUN_UNIT_TESTS=OFF
• cmake --build build-s3crt --config Release --target aws-cpp-sdk-s3-crt -- /m

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