Fixed regex to pick correct items (#42557)

(cherry picked from commit fa624eba29)

lib/ansible/modules/network/ios/ios_linkagg.py

@@ -227,7 +227,7 @@ def parse_members(module, config, group):
 
 
 def get_channel(module, config, group):
-    match = re.findall(r'interface (\S+)', config, re.M)
+    match = re.findall(r'^interface (\S+)', config, re.M)
 
     if not match:
         return {}