[BUGS-3638] Handle error processing workflow in connection:set comman…

…d. (#2563)

* Handle 400 error in connection:set command.

* Fix linter.

* Fix linter.

* We should check now on workflow processing.

* Coding standards.

* Update src/Commands/Connection/SetCommand.php

Co-authored-by: Brian Weaver <87093053+namespacebrian@users.noreply.github.com>

---------

Co-authored-by: Brian Weaver <87093053+namespacebrian@users.noreply.github.com>

src/Commands/Connection/SetCommand.php

@@ -73,7 +73,18 @@ public function connectionSet($site_env, $mode)
             throw $e;
         }
 
-        $this->processWorkflow($workflow);
+        try {
+            $this->processWorkflow($workflow);
+        } catch (TerminusException $e) {
+            if (strpos($e->getMessage(), 'build_status is building') !== false) {
+                throw new TerminusException(
+                    'Cannot switch to SFTP mode because the most recent Integrated Composer build ' .
+                    'is either still running or encountered errrors.' .
+                    'Please check your latest commit in the dashboard.'
+                );
+            }
+            throw $e;
+        }
         $this->log()->notice($workflow->getMessage());
     }
 }