Quick follow up to bug 526733 landing change 'this' to 'the' as suggested in the ui-review but not done in original push

mail/locales/en-US/chrome/messenger/messenger.properties

@@ -514,7 +514,7 @@ loadingTab=Loading…
 # LOCALIZATION NOTE (xpinstallPromptWarning):
 # %1$S is replaced by brandShortName, %2$S is replaced by the host name of the
 # site.
-xpinstallPromptWarning=%1$S prevented this site (%2$S) from asking you to install software on your computer.
+xpinstallPromptWarning=%1$S prevented the site (%2$S) from asking you to install software on your computer.
 xpinstallPromptAllowButton=Allow
 # LOCALIZATION NOTE (xpinstallPromptAllowButton.accesskey):
 # Accessibility Note: