[GEN][ZH] Downgrade debug assertion to log for isPathInDirectory

[slurmlord]

• Follow up for [GEN][ZH] Fix security issue in map transfer by validating file paths when creating real paths from portable paths #1058

#1058 added a new check for testing if a file is under a specific base path. In case it was not, a DEBUG_CRASH was triggered, before returning false.
This leads to an assert when starting the shell map, as the code in GameLogic::startNewGame explicitly sanity checks that the map is not in the save directory.
This type of sanity checking should not cause assertion failures or debug logging, so it's better to move the responsibility for reacting to those cases to the caller. This change removes the DEBUG_CRASH from FileSystem::isPathInDirectory, downgrades is to a DEBUG_LOG and places it in GameState::portableMapPathToRealMapPath.

[xezon]

Wouldn't that mean, this Debug Log is printed for start a new game for any (official) map that is in the Game Install directory (in MapsZH.big)? Is that the way it should be?

[slurmlord]

Yes, I agree, that would be needless log entries that causes more confusion for someone reading the logs than help.
I think the logging should be removed from the "false"-case in isPathInDirectory and instead just move something similar to it into the "false"-case in GameState::portableMapPathToRealMapPath:

	if (!FileSystem::isPathInDirectory(prefix, containingBasePath))
	{
		DEBUG_LOG(("Error here"));
		return AsciiString::TheEmptyString;
	}

That way it's only logged if the file is not in the expected path instead of "not being in an unexpected path" like the case now.