[Bug] Http2ProtocolProxyHandler.match throws on short ByteBuf

### Before Creating the Bug Report

- [x] I have searched the existing issues and pull requests.

### Runtime platform environment

N/A

### RocketMQ version

develop branch

### JDK Version

N/A

### Describe the Bug

`Http2ProtocolProxyHandler.match(ByteBuf in)` calls `in.getInt(in.readerIndex())` directly after checking `enableRemotingLocalProxyGrpc`.

If the protocol detector receives an empty or short buffer with fewer than 4 readable bytes, Netty can throw `IndexOutOfBoundsException` instead of returning `false` and letting the protocol detection pipeline wait for more data or reject the message safely.

### Steps to Reproduce

1. Enable remoting local proxy gRPC protocol detection.
2. Call `Http2ProtocolProxyHandler.match()` with a `ByteBuf` containing fewer than 4 readable bytes.
3. Observe that `getInt(readerIndex)` can throw because the handler does not check `readableBytes()` first.

### What Did You Expect to See?

Short buffers should not crash protocol detection. `match()` should return `false` until enough bytes are available to compare the HTTP/2 `PRI ` prefix.

### What Did You See Instead?

`match()` can throw `IndexOutOfBoundsException` for short buffers.

### Additional Context

This is in the Proxy remoting/gRPC ingress path and is a small runtime robustness fix.

Start at Http2ProtocolProxyHandler.match(ByteBuf in) and inspect the readable-byte handling before the HTTP/2 PRI prefix comparison. Reproduce the behavior with empty and fewer-than-four-byte ByteBuf inputs; done means match returns false without IndexOutOfBoundsException while normal prefix detection still works.

Written by the indexing model from the issue text.