fix: iOS crash when BlobModule is nil in RCTNetworking initialization

[hoonjoo-park]

Summary:

An iOS crash occurs during networking module initialization in uncertain situations. This happens in the RCTAppSetupUtils.mm file when setting up URL handlers for the RCTNetworking class and BlobModule is nil.

this PR fixes this issue #50210

Changelog:

[IOS] [FIXED] - Fix app crash in RCTNetworking when BlobModule is nil by adding null check before adding it to handlers array

Test Plan:

1. Created a test environment where BlobModule is not available/initialized
2. Before the fix, the app crashes when attempting network requests with the error: "Collection element of type 'std::nullptr_t' is not an Objective-C object"
3. After applying the fix, the app successfully initializes the networking module without crashing
4. Verified network requests work properly even when BlobModule is not available
5. Also verified that when BlobModule is properly initialized, it still works as expected with all functionality intact

[cipolleschi]

Hi thanks for the PR. However, I don't think we can merge it.
The BlobModule is something provided by React Native and the module needs to be part of those handlers or some features will stop working.

Rather than fixing it this way, I would like to understand better why the BlobModule is not initialized properly in your app.

This fix will cure a symptom, not the root cause.

[hoonjoo-park]

@cipolleschi I fully agree with your assessment. 👍
I’m aware that the PR I submitted is likely not a good solution, and I'm still investigating the root cause of why BlobModule is not being initialized.
Based on our crash reports, the issue predominantly occurs on older devices such as the iPhone 7 Plus and iPhone 6.

[cipolleschi]

it would help if you can tell us about what the user is doing in the app.
Is perhaps navigating quickly from a RN surface to a native surface and back to a RN one?
The assumption is that there might be a race condition when React Native is teared down and recreated.