fix(replay): Fix visual artifacts for the Canvas strategy on some devices

[romtsn]

📜 Description

• Switch to PixelCopy for capturing surface backed by the Picture in CanvasStrategy
• Use the same background handler for both PixelCopy and pictureRenderTask to avoid thread context switch

Example replay: https://sentry-sdks.sentry.io/explore/replays/09456bd8f08c43eb862a23759d1dc640

💡 Motivation and Context

Closes #4857

💚 How did you test it?

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[sentry]

Bug: Unsynchronized access to screenshot Bitmap by multiple threads while another thread recycles it.
_{Severity: CRITICAL | Confidence: 1.00}

🔍 Detailed Analysis

The screenshot Bitmap is accessed without synchronization by emitLastScreenshot() on the main thread and by the PixelCopy callback on a background handler thread. Concurrently, the close() method, executing on a thread pool, recycles the same screenshot Bitmap. This creates a data race where the Bitmap can be accessed after it has been recycled, which can lead to native crashes according to repository guidelines.

💡 Suggested Fix

Protect all accesses to the screenshot Bitmap with synchronized(bitmap) blocks to prevent concurrent access during recycling or other operations.

🤖 Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location:
sentry-android-replay/src/main/java/io/sentry/android/replay/screenshot/CanvasStrategy.kt#L104-L110

Potential issue: The `screenshot` Bitmap is accessed without synchronization by
`emitLastScreenshot()` on the main thread and by the PixelCopy callback on a background
handler thread. Concurrently, the `close()` method, executing on a thread pool, recycles
the same `screenshot` Bitmap. This creates a data race where the Bitmap can be accessed
after it has been recycled, which can lead to native crashes according to repository
guidelines.

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	319.29 ms	412.76 ms	93.47 ms
Size	1.58 MiB	2.12 MiB	551.78 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
2124a46	319.19 ms	415.04 ms	95.85 ms
b3d8889	420.46 ms	453.71 ms	33.26 ms
d217708	409.83 ms	474.72 ms	64.89 ms
3d205d0	352.15 ms	432.53 ms	80.38 ms
fcec2f2	357.47 ms	447.32 ms	89.85 ms
889ecea	367.58 ms	437.52 ms	69.94 ms
1df7eb6	397.04 ms	429.64 ms	32.60 ms
ce0a49e	532.00 ms	609.96 ms	77.96 ms
ee747ae	357.79 ms	421.84 ms	64.05 ms
b750b96	408.98 ms	480.32 ms	71.34 ms

App size

Revision	Plain	With Sentry	Diff
2124a46	1.58 MiB	2.12 MiB	551.51 KiB
b3d8889	1.58 MiB	2.10 MiB	535.07 KiB
d217708	1.58 MiB	2.10 MiB	532.97 KiB
3d205d0	1.58 MiB	2.10 MiB	532.97 KiB
fcec2f2	1.58 MiB	2.12 MiB	551.50 KiB
889ecea	1.58 MiB	2.11 MiB	539.75 KiB
1df7eb6	1.58 MiB	2.10 MiB	532.97 KiB
ce0a49e	1.58 MiB	2.10 MiB	532.94 KiB
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
b750b96	1.58 MiB	2.10 MiB	533.19 KiB

Previous results on branch: rz/fix/session-replay-canvas-artifacts

Startup times

Revision	Plain	With Sentry	Diff
a47b2db	372.31 ms	463.36 ms	91.05 ms
51bd5cc	360.74 ms	464.40 ms	103.65 ms
bd9a863	300.79 ms	361.92 ms	61.13 ms
7e17e61	314.77 ms	337.06 ms	22.29 ms

App size

Revision	Plain	With Sentry	Diff
a47b2db	1.58 MiB	2.12 MiB	551.78 KiB
51bd5cc	1.58 MiB	2.12 MiB	551.66 KiB
bd9a863	1.58 MiB	2.12 MiB	551.65 KiB
7e17e61	1.58 MiB	2.12 MiB	551.75 KiB

[markushi]