Permissions on remote schema enum causing parsing errors

### Version Information

Server Version: v2.0.8
CLI Version (for CLI related issue): v2.0.3

### Environment

### What is the expected behaviour?
When my remote schemas contains enums and I need to apply permissions to them, the standard format without newlines should apply, or the engine should properly parse out newlines

### Keywords

### What is the current behaviour?
One of my remote schemas contains an enum of strings, and I have custom permissions for different users on accessing these fields. However, having enums causes the console to use line breaks between the strings, and the next time I start the engine I receive a remote schema parsing error.

My workaround has been to remove all lines breaks from the metadata and make the entire permission one line. However, if I modify one permission or sometimes modify another permission in the console. it will cause the metadata to restore the default format with the newlines, and I have to keep repeating the cycle.

I can confirm that when I delete the enum fields from my remote schema and reload the metadata, the console creates a format without newlines that is recognized by the engine.

I feel like this is a very easy fix but I don't know Haskell 😅.

I'm using TypeGraphQL to make my remote schemas.

### How to reproduce the issue?

1. Create a remote schema with enum string fields.
2. From the console, apply remote schema permissions to all fields including the enum
3. Restart the engine, or apply metadata again.

Workarounds:

1. Remove all newlines from remote schema permission and format the entire string into one line
2. Remove enum fields, apply new permissions and reload metadata.

### Screenshots or Screencast
Remote schema metadata with newlines


### Please provide any traces or logs that could help here.
Stack trace when starting engine (using **hasura/graphql-engine:v2.0.8.cli-migrations-v3**)

` time="2021-09-17T16:25:22Z" level=fatal msg="error applying metadata \n{\n \"path\": \"$.args.metadata.remote_schemas[1].permissions[1].definition.schema\",\n \"error\": \"parsing the schema document: \\\"endOfInput\\\"\",\n \"code\": \"parse-failed\"\n}"`

### Any possible solutions?

### Can you identify the location in the source code where the problem exists?

### If the bug is confirmed, would you be willing to submit a PR?

Start with the metadata.remote_schemas permissions definition.schema path and reproduce the issue using enum fields, console permissions, and a metadata reload or engine restart. Trace the schema-document parser for the reported endOfInput error; done means console-generated permissions containing newlines are accepted without requiring manual reformatting.

Written by the indexing model from the issue text.