Removed superfluous echo preventing T1553.004 from running update-ca-certificates (#3095)

Co-authored-by: Cauan Guimarães <c.guimaraes[]gmail.com>
Co-authored-by: Carrie Roberts <clr2of8@gmail.com>

atomics/T1553.004/T1553.004.md

@@ -141,7 +141,7 @@ Creates a root CA with openssl
 
 ```sh
 mv #{cert_filename} /usr/local/share/ca-certificates
-echo sudo update-ca-certificates
+sudo update-ca-certificates
 ```
 
 

atomics/T1553.004/T1553.004.yaml

@@ -80,7 +80,7 @@ atomic_tests:
   executor:
     command: |
       mv #{cert_filename} /usr/local/share/ca-certificates
-      echo sudo update-ca-certificates
+      sudo update-ca-certificates
     name: sh
     elevation_required: true
 - name: Install root CA on macOS