Simplify wildcard JSON searching

[psrok1]

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• I've read the contributing guideline.
• I've tested my changes by building and running the project, and testing changed functionality (if applicable)
• I've added automated tests for my change (if applicable, optional)
• I've updated documentation to reflect my change (if applicable)

What is the current behaviour?

JSON search code is pretty complicated because it assumes that wildcard search that is not a full-text search (with wildcards on both sides *value*) can also search for nested objects, so it needs to look for two possible combinations of escaping:

• quoted values {"key": {"current_dir": "C:\\Windows"}} so cfg.key:*C:\\Windows* needs to search for LIKE '%C:\\\\Windows' as the value returned by json_path_query(cfg, '$.key') #>> '{}' is {"current_dir": "C:\\Windows"}
• unquoted values {"key": "C:\Windows"} so cfg.key:"C:\\Windows*" needs to search for LIKE "C:\\Windows%" as the value returned by json_path_query(cfg, '$.key') #>> '{}' is C:\Windows

What is the new behaviour?

We just assume that nested objects can be searched only with full-text search. When search is not full-text, we assume that we match only against literal, which simplifies query.