Fixes an issue with completely empty hard drives

If empty hard drives are being set up for the first time, then `.has_content()`'s `mount` call will fail with `wrong fstype` since there's no filesystem yet. First step in this case is to check for that scenario, then check for content.

archinstall/lib/disk.py

@@ -204,6 +204,9 @@ class Partition():
 			return None
 
 	def has_content(self):
+		if not get_filesystem_type(self.path):
+			return False
+		
 		temporary_mountpoint = '/tmp/'+hashlib.md5(bytes(f"{time.time()}", 'UTF-8')+os.urandom(12)).hexdigest()
 		temporary_path = pathlib.Path(temporary_mountpoint)
 
@@ -529,4 +532,4 @@ def get_filesystem_type(path):
 		handle = sys_command(f"blkid -o value -s TYPE {path}")
 		return b''.join(handle).strip().decode('UTF-8')
 	except SysCallError:
-		return None
+		return None