Updated system apps exclusion copy (#4552)

Task/Issue URL:
https://app.asana.com/0/38424471409662/1207344664175730/f

### Description
Updated copy from "when" to "if"

### Steps to test this PR

N/A

network-protection/network-protection-impl/src/main/res/values/donottranslate.xml

@@ -148,7 +148,7 @@
     <!-- System apps exclusion list -->
     <string name="netpExclusionListSystemAppsHeader">Android System Apps</string>
     <string name="netpExclusionListWarningTitle">About System App Exclusions</string>
-    <string name="netpExclusionListWarningMessage">Internet traffic, including background connections, used by this group of apps won\'t be protected by the VPN. Consider re-enabling when this doesn\'t fix the issue to prevent unexpected data leaks.</string>
+    <string name="netpExclusionListWarningMessage">Internet traffic, including background connections, used by this group of apps won\'t be protected by the VPN. Consider re-enabling if this doesn\'t fix the issue to prevent unexpected data leaks.</string>
     <string name="netpExclusionListWarningActionPositive">OK</string>
 
     <!-- About -->