fix(fragment-matcher): don't introspect a schema that declares @defer/@stream - #10927

Fixes #10894.

graphql 17's execute() refuses to run against a schema that declares @defer or @stream, whether
or not the document uses them. The introspection query here doesn't use either, but having @defer in
the SDL is enough to kill codegen. We declare it so @graphql-eslint picks it up in operations, and
there's no config option to skip past this.

Introspect a copy without them instead:

const cleanSchema =
  federationlessSchema.getDirective('defer') || federationlessSchema.getDirective('stream')
    ? new GraphQLSchema({
        ...federationlessSchema.toConfig(),
        directives: federationlessSchema
          .getDirectives()
          .filter(d => d.name !== 'defer' && d.name !== 'stream'),
      })
    : federationlessSchema;

Only rebuilds when one of them is actually declared, so nothing changes otherwise.

Output is unaffected. The same schema on graphql 16 unpatched and on graphql 17 patched both give:

{ "possibleTypes": { "Node": ["User", "Post"], "Content": ["User", "Post"] } }

Also ran it across our own codegen configs, generated output unchanged.

The test can't fail on the graphql 16 pinned here, since 16's execute() doesn't throw. It starts
guarding properly whenever the repo moves to 17.