Remove the rewrite_imports preamble

[mfridman]

I think we should consider removing the rewrite_imports preamble from the generated code. It's more of an implementation detail (and feature) of the BSR. By removing this we get:

1. cleaner generated code.
2. ability to improve the underlying glob patterns upstream without affecting the imports. We likely don't want to do this, but if we do then it'll be seamless to the user without diff changes.
3. this is helpful for debugging, but an issue with this chunk of code will still result in the wrong import path. So that's the thing the end-user should be focusing on, and less on this option.

// @generated by protoc-gen-connect-web v0.3.3 with parameter "rewrite_imports=./pet/v1/**/*_pb.js:@buf/acme_petapis.bufbuild_es,rewrite_imports=./payment/v1alpha1/**/*_pb.js:@buf/acme_paymentapis.bufbuild_es,rewrite_imports=./payment/v1alpha1/**/*_connectweb.js:@buf/acme_paymentapis.bufbuild_connect-web,rewrite_imports=./google/type/**/*_pb.js:@buf/googleapis_googleapis.bufbuild_es,rewrite_imports=./google/type/**/*_connectweb.js:@buf/googleapis_googleapis.bufbuild_connect-web"
// @generated from file pet/v1/pet.proto (package pet.v1, syntax proto3)
/* eslint-disable */
// @ts-nocheck