Reduce data network validation result message handle.

The post() method needs to be reduced.
Sometimes the actual network validation status (validated) would
indicate earlier than the result of the network validation request.
To fix this, we decreased the message handling process by 1.

Bug: 372495133
Test: FrameworksTelephonyTests
Test: Verified @ b/372495133#comment10
Flag: EXEMPT bugfix
Change-Id: I814e76a3ba7bef1a6029d8f04ecbb92508fa0d96