fix(iOS): Fix ephemeralSession parameter type conversion in webAuth

[subhankarmaiti]

What

Fixes the ephemeralSession parameter type conversion in the iOS native webAuth method implementation.

Why

The ephemeralSession parameter was being passed directly as an NSNumber to the native bridge without proper boolean conversion. This could cause issues when the native Swift code expects a proper boolean value.

How

• Added explicit boolean conversion using [ephemeralSession boolValue] before passing to the native bridge
• This ensures the parameter is properly converted from NSNumber to BOOL type as expected by the Swift implementation

Testing

• Verified that ephemeralSession: true works correctly on iOS
• Verified that ephemeralSession: false works correctly on iOS
• Confirmed no regression in existing webAuth functionality

Fixes #1232