Rename icon to prevent install conflicts with the Qt6 frontend.

--- qt5/pinentryrc.qrc.orig	2024-07-03 09:19:19 UTC
+++ qt5/pinentryrc.qrc
@@ -2,7 +2,7 @@
 <RCC version="1.0">
 <qresource>
     <file>icons/data-error.svg</file>
-    <file>icons/pinentry.png</file>
+    <file>icons/pinentry-qt5.png</file>
     <file>icons/hint.svg</file>
     <file>icons/password-generate.svg</file>
     <file>icons/visibility.svg</file>