bug symfony#54440 [Console] return null when message with name is not set (xabbuh)

This PR was merged into the 5.4 branch.

Discussion
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[Console] return null when message with name is not set

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

same as symfony#54419 but for the `5.4` branch

Commits
-------

050d8e8 return null when message with name is not set

Author: xabbuh

src/Symfony/Component/Console/Helper/ProgressBar.php

@@ -169,9 +169,12 @@ public function setMessage(string $message, string $name = 'message')
         $this->messages[$name] = $message;
     }
 
+    /**
+     * @return string|null
+     */
     public function getMessage(string $name = 'message')
     {
-        return $this->messages[$name];
+        return $this->messages[$name] ?? null;
     }
 
     public function getStartTime(): int

src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php

@@ -1173,4 +1173,11 @@ public function testMultiLineFormatIsFullyCorrectlyWithManuallyCleanup()
             stream_get_contents($output->getStream())
         );
     }
+
+    public function testGetNotSetMessage()
+    {
+        $progressBar = new ProgressBar($this->getOutputStream());
+
+        $this->assertNull($progressBar->getMessage());
+    }
 }