Add EF.Functions.JsonExists(expression, path) DbFunction

[mseada94]

• Fixes Relational method for checking whether a path in a JSON exists #31136

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        Fixes #bugnumber

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TODO

• Define relational level EF.Functions.JsonExists DbFunction
• Define SqlServer translation
• Define Sqllite translation
• Add test for constant json expression translation success
• Add test for column (string) json expression translation success
• Add test for column (owned) json expression translation success
• Add test for column (string value converter) json expression translation success
• Add test for column (not of the previous types) json expression translation failure
• Add function test for 3 cases of the result (true, false, null)

Design notes:

• The json expression is being tested before translation to allows only
  • String expressions (column, constant, complex)
  • Owned JSON column expression
  • Column with string value converter expression
• In SQL Server, EF.Functions.JsonExists translate to JSON_PATH_EXISTS function which require SQL Server 2022.
• In SQLite, EF.Functions.JsonExists translate to the following expression using JSON_TYPE function, as the best available equivalent for JsonExists at the moment.
  IIF(arguments_0 IS NULL, NULL, JSON_TYPE(arguments_0, arguments_1) IS NOT NULL)

CASE 
    WHEN arguments_0 IS NOT NULL THEN JSONT_YPE(arguments_0, arguments_1) IS NOT NULL
    ELSE NULL
END

• The nullability of the second argument is not considered, generally user should not use null json path when calling this function
  • In SQL Server there will be an error
  • In SQLite JSON_TYPE will return NULL which will result in FALSE to be returned from this expression