Removed install Q notification if Q is already installed (#4449)

Author: wularr

.changes/next-release/bugfix-d9e51383-075c-4253-b9c5-3e7c588c2605.json

@@ -0,0 +1,4 @@
+{
+  "type" : "bugfix",
+  "description" : "Removed install Q notification if Q is already installed"
+}

plugins/toolkit/jetbrains-core/src/software/aws/toolkits/jetbrains/core/startup/QMigrationActivity.kt

@@ -4,6 +4,7 @@
 package software.aws.toolkits.jetbrains.core.startup
 
 import com.intellij.ide.BrowserUtil
+import com.intellij.ide.plugins.PluginManager
 import com.intellij.ide.plugins.PluginManagerConfigurable
 import com.intellij.ide.plugins.PluginManagerCore
 import com.intellij.ide.plugins.PluginManagerMain
@@ -54,7 +55,7 @@ class QMigrationActivity : StartupActivity.DumbAware {
         if (hasUsedCodeWhisperer || hasUsedQ) {
             // do auto-install
             installQPlugin(project, autoInstall = true)
-        } else {
+        } else if (!PluginManager.isPluginInstalled(PluginId.getId(AwsToolkit.Q_PLUGIN_ID))) {
             // show opt-in/install notification
             notifyInfo(
                 title = message("aws.q.migration.new_users.notify.title"),