Quote JSON path segments for query accessor.

[kleinmann]

1. Why is this change necessary?

Usage of hyphenated fields in JSON fields in a DAL query currently results in a MySQL error "Invalid JSON path expression". Such fields must be quoted to be used in a query.

2. What does this change do, exactly?

It quotes all segments (separated by .) when building the field accessor for the MySQL query.

3. Describe each step to reproduce the issue or behaviour.

• Create a custom field "my-hyphenated-field"
• Use the custom field in a query:

$criteria->addFilter(new EqualsFilter('customFields.my-hyphenated-field', 'some value'));

• See error during execution

4. Please link to the relevant issues (if any).

There's no issue yet, as far as I can tell.

5. Checklist

• I have written tests and verified that they fail without my change
• I have squashed any insignificant commits
• I have created a changelog file with all necessary information about my changes
• I have written or adjusted the documentation according to my changes
• This change has comments for package types, values, functions, and non-obvious lines of code
• I have read the contribution requirements and fulfil them.

[kleinmann]

I am not sure if all relevant use cases of this accessor builder are present in my test. Suggestions would be much appreciated.

[kleinmann]

Upon further testing and checking other cases from the failing tests, I think this can be solved more easily by adding quotes (like customFields."my-hyphenated-fields") directly in the filter arguments. I'm closing this PR :-)