fix(grpc-transcode): filter out illegal INT(string) formats

[zhoujiexiong]

Description

Need to sync. lua-protobuf lib. updated by this PR(https://github.com/starwing/lua-protobuf/pull/269).

Fixes #11355

Checklist

• [x] I have explained the need for this PR and the problem it solves
• [x] I have explained the changes or the new features added to this PR
• [x] I have added tests corresponding to this change
• [x] I have updated the documentation to reflect this change
• [x] I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)