bug symfony#45925 [RateLimiter] Add typecase to SlidingWindow::getExpirationTime (georgringer)

This PR was squashed before being merged into the 5.4 branch.

Discussion
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[RateLimiter] Add typecase to SlidingWindow::getExpirationTime

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix symfony#45924
| License       | MIT

Commits
-------

de8a2c2 [RateLimiter] Add typecase to SlidingWindow::getExpirationTime

Author: nicolas-grekas

src/Symfony/Component/RateLimiter/Policy/SlidingWindow.php

@@ -76,7 +76,7 @@ public function getId(): string
      */
     public function getExpirationTime(): int
     {
-        return $this->windowEndAt + $this->intervalInSeconds - microtime(true);
+        return (int) ($this->windowEndAt + $this->intervalInSeconds - microtime(true));
     }
 
     public function isExpired(): bool

src/Symfony/Component/RateLimiter/Tests/Policy/SlidingWindowTest.php

@@ -34,6 +34,9 @@ public function testGetExpirationTime()
 
         $new = SlidingWindow::createFromPreviousWindow($cachedWindow, 15);
         $this->assertSame(2 * 15, $new->getExpirationTime());
+
+        usleep(10.1);
+        $this->assertIsInt($new->getExpirationTime());
     }
 
     public function testInvalidInterval()