Fix: avoid dangling pointer when reading runtime shader child name

[subraatakumar]

Prevent a dangling pointer by keeping the UTF‑8 string returned from JSI alive before calling c_str().

Root cause:
Code called arguments[1].asString(runtime).utf8(runtime).c_str() on a temporary; the temporary is destroyed at the end of the full-expression, producing a dangling pointer and triggering clang’s -Wdangling-assignment-gsl (failing Android native builds).

Change:
Store the UTF‑8 value in a local std::string and use childName = childNameStr.c_str() so the backing storage remains valid.

Files changed:

• packages/skia/cpp/api/JsiSkImageFilterFactory.h

Testing / Verification:

• Before: Android native build failed with -Wdangling-assignment-gsl pointing to JsiSkImageFilterFactory.h.
• After: Rebuilt downstream app/native module; Android native build succeeds and clang no longer emits the dangling-assignment warning.
• Reproduction: ./gradlew :app:assembleDebug in a project that builds this module.

Reviewer checklist:

• Confirm the clang dangling-pointer diagnostic is gone.
• Confirm no API or behavior changes beyond lifetime fix.
• Run Android native build as a smoke test.

[subraatakumar]

I have signed the CLA!

[subraatakumar]

I have signed the CLA!

[subraatakumar]

Apologies — I closed the PR by mistake.
Thanks again for the review and approval. Happy to address any follow-ups if needed.