:electron: Update flathub screenshots to meet quality guidelines (#6611)

* update desktop app screenshots to meet quality guidelines

* better comply with flathub quality guidelines

* screenshot updates

packages/desktop-electron/extra-resources/linux/com.actualbudget.actual.metainfo.xml

@@ -2,7 +2,7 @@
 <component type="desktop">
   <id>com.actualbudget.actual</id>
   <name>Actual Budget</name>
-  <summary>Your Finances - made simple</summary>
+  <summary>Your Finances made simple</summary>
   <metadata_license>MIT</metadata_license>
   <project_license>MIT</project_license>
   <content_rating type="oars-1.0" />
@@ -28,37 +28,21 @@
     <control>touch</control>
   </recommends>
   <screenshots>
-    <screenshot type="default" environment="gnome:dark">
-      <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/budget-gnome-dark.png</image>
-      <caption>Budget screen (dark theme)</caption>
-    </screenshot>
-    <screenshot environment="gnome">
+    <screenshot type="default" environment="gnome">
       <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/budget-gnome-light.png</image>
-      <caption>Budget screen (light theme)</caption>
-    </screenshot>
-    <screenshot environment="gnome:dark">
-      <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/transactions-gnome-dark.png</image>
-      <caption>Transactions screen (dark theme)</caption>
+      <caption>Budget screen</caption>
     </screenshot>
     <screenshot environment="gnome">
       <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/transactions-gnome-light.png</image>
-      <caption>Transactions screen (light theme)</caption>
-    </screenshot>
-    <screenshot environment="gnome:dark">
-      <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/schedules-gnome-dark.png</image>
-      <caption>Schedules screen (dark theme)</caption>
+      <caption>Transactions screen</caption>
     </screenshot>
     <screenshot environment="gnome">
       <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/schedules-gnome-light.png</image>
-      <caption>Schedules screen (light theme)</caption>
-    </screenshot>
-    <screenshot environment="gnome:dark">
-      <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/reports-gnome-dark.png</image>
-      <caption>Reports screen (dark theme)</caption>
+      <caption>Schedules screen</caption>
     </screenshot>
     <screenshot environment="gnome">
       <image type="source">https://raw.githubusercontent.com/actualbudget/actual/master/packages/desktop-electron/screenshots/reports-gnome-light.png</image>
-      <caption>Reports screen (light theme)</caption>
+      <caption>Reports screen</caption>
     </screenshot>
   </screenshots>
   <releases>