Add from() and findDetails() to ConnectError

[timostamm]

This adds two methods to ConnectError:

The static from(), which converts any error into a ConnectError, if it is not already a ConnectError:

try {
  // call an RPC
} catch (e) {
  const err: ConnectError = ConnectError.from(reason);
  console.log(err.message);
  console.log(err.code == Code.ResourceExhausted);
} 

This is a replacement for connectErrorFromReason(), which is deprecated with this PR. The static method is more discoverable, and it does not require a separate import.

And the instance method findDetails():

import {ConnectError} from "@bufbuild/connect-web";
import {LocalizedMessage} from "./error_details_pb.js";

function handle(err: ConnectError) {
  const localized = err.findDetails(LocalizedMessage)
    .find(i => i.locale === navigator.language);
  console.log(localized?.message);
}

This is a replacement for connectErrorDetails(), which is deprecated with this PR. The instance method is more discoverable, does not require a separate import, and has a more descriptive name.

The standalone function has one override accepting multiple message types that the new method does not implement. The simple workaround is to use a registry:

- connectErrorDetails(err, TypeA, TypeB);
+ import { createRegistry } from "@bufbuild/protobuf";
+ err.findDetails(createRegistry(TypeA, TypeB));

This change adds 1% to the bundle size according to our code size comparison, but the improved developer experience seems worth it.