Add function to obtain filesystem type from DirAccess.

Change EditorFileSystem to not use directory modification times on FAT32, fixes #20946

core/io/file_access_pack.h

@@ -221,6 +221,9 @@ public:
 
 	size_t get_space_left();
 
+	virtual String get_filesystem_type() const;
+
+
 	DirAccessPack();
 	~DirAccessPack();
 };