fix(attachment): handle transient prefix

[CoderPoet]

What type of PR is this?

fix(attachment): When encoding and decoding attachments, handle transient prefixes correctly

Check the PR title.

• [x] This PR title match the format: \<type>(optional scope): \<description>
• [x] The description of this PR title is user-oriented and clear enough for others to understand.
• [x] Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo

Test Cases

1. dubbo-java-client -> kitex-go-server

2. kitex-go-client -> dubbo-java-server

3. kitex-go-client -> kitex-go-server

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