Cosmos: Add translator for Substring method which map to SUBSTRING built-in functions

[Marusyk]

Add translator for string.Substring()

Issue #16143

Please review.
Thank you in advance

[roji]

Thanks for all these translation contributions @Marusyk!

Can you please try enabling NorthwindWhereQueryCosmosTest.Where_string_substring as well? Note that there are other skipped tests for Trim/TrimStart/TrimEnd in NorthwindFunctionsQueryCosmosTest, can you please check those too?

Finally, if you intending to submit more string translations, may I suggest submitting them in a single PR rather than a PR-per-translation? This simplifies the review process and the general project history.

[Marusyk]

Thanks for all these translation contributions @Marusyk!

Not at all! I need this for my work

Finally, if you intending to submit more string translations, may I suggest submitting them in a single PR rather than a PR-per-translation? This simplifies the review process and the general project history.

@roji, I will but, I do it in my spare time, so, when I have time to add more than one translation, then I will do it within one PR. But when I have time to add only one translation, I don't see a problem in doing it within different PRs.
Or do you suggest not submit more PRs until I make all the string translations?

Translations are separate parts of the functionality that are not dependent on each other in most cases. Could you please explain how this can affect the general history of the project?

if you intending to submit more string translations, may I suggest submitting them in a single PR

What if I want to submit only a few of them? Only one of them? What if I want to submit one today and the other in the next week? Should I wait 2 weeks and then merge conflicts in that case?
Please explain the problem in a PR-per-translation

[Marusyk]

Note that there are other skipped tests for Trim/TrimStart/TrimEnd in NorthwindFunctionsQueryCosmosTest, can you please check those too?

All of them are not relevant because Cosmos DB TRIM/LTRIM/RTRIM does not take arguments (the same as SQL Server)

efcore/src/EFCore.Cosmos/Query/Internal/StringMethodTranslator.cs

Lines 138 to 160 in 1da7f89

	if (_trimStartMethodInfoWithoutArgs?.Equals(method) == true
	|| (_trimStartMethodInfoWithCharArrayArg.Equals(method)
	// Cosmos DB LTRIM does not take arguments
	&& ((arguments[0] as SqlConstantExpression)?.Value as Array)?.Length == 0))
	{
	return TranslateSystemFunction("LTRIM", method.ReturnType, instance);
	}
	if (_trimEndMethodInfoWithoutArgs?.Equals(method) == true
	|| (_trimEndMethodInfoWithCharArrayArg.Equals(method)
	// Cosmos DB RTRIM does not take arguments
	&& ((arguments[0] as SqlConstantExpression)?.Value as Array)?.Length == 0))
	{
	return TranslateSystemFunction("RTRIM", method.ReturnType, instance);
	}
	if (_trimMethodInfoWithoutArgs?.Equals(method) == true
	|| (_trimMethodInfoWithCharArrayArg.Equals(method)
	// Cosmos DB TRIM does not take arguments
	&& ((arguments[0] as SqlConstantExpression)?.Value as Array)?.Length == 0))
	{
	return TranslateSystemFunction("TRIM", method.ReturnType, instance);
	}

[maumar]

@Marusyk thank you for the contribution!