fix: allow escape characters in json parsing [CFG-1322]

[teodora-sandu]

What does this PR do?

This PR fixes the bug in https://snyksec.atlassian.net/browse/CFG-1322 by making sure if the parsed file is JSON we don't fail upon finding \\/.

How should this be manually tested?

In snyk/cloud-config-parser#39:

1. npm run build
2. npm link

In this branch:

1. npm run build
2. Create a file test.json containing:

{
      "DescribePackagesFilterValue":{
        "type":"string",
        "pattern":"^[0-9a-zA-Z\\*\\.\\\\/\\?-]*$"
      }
}

3. Run snyk iac test test.json - see an error
4. Run snyk-dev iac test test.json - see no errors

Any background context you want to provide?

A while ago we combined the parsing for JSON and YAML to both use the YAML parser, since they are more or less the same. We know from https://snyksec.atlassian.net/browse/CFG-364, however, that \\/ is not valid YAML - and we added this check that throws an error when a YAML/JSON file contains \\/. Now, we're improving this logic so that if the content is JSON, we don't throw an error.

What are the relevant tickets?

https://snyksec.atlassian.net/browse/CFG-1322

Screenshots

snyk iac test test.json

snyk-dev iac test test.json

[github-actions]

	Warnings
⚠️	You've modified files in src/ directory, but haven't updated anything in test folder. Is there something that could be tested?

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