Fix: Make sure bindings work after page restored from bfcache

[kblok]

Summary

• Adds a CDP binding prefix (puppeteer_) to all Runtime.addBinding and Runtime.removeBinding calls, matching upstream Puppeteer's approach
• Updates the JavaScript addPageBinding function to use the prefix when calling the CDP binding, avoiding name collisions when pages are restored from the back-forward cache
• Removes the Symbol.toStringTag check in favor of checking globalThis[name] to detect already-wrapped bindings
• Adds a test verifying that ExposeFunctionAsync works correctly after navigating back to a BFCached page

Upstream PR

puppeteer/puppeteer#12663

Closes #2682

Changes

File	Change
BindingUtils.cs	Added CdpBindingPrefix constant; updated JS addPageBinding to accept prefix param and use globalThis[prefix + name]()
IsolatedWorld.cs	Prepend CdpBindingPrefix to binding name in Runtime.addBinding call
CdpPage.cs	Prepend CdpBindingPrefix to binding name in Runtime.addBinding and Runtime.removeBinding calls
BFCacheTests.cs	Added test for calling exposed functions after bfcache restoration

Test plan

• BFCache tests pass (3/3)
• ExposeFunctionTests pass (13/13)
• PageEvaluateTests pass
• ARIA selector tests pass (10/10)

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