Make internal mode controlled from execution arguments

.idea/runConfigurations/IDEA__Not_Internal_.xml

@@ -0,0 +1,19 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="IDEA (Not Internal)" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="-Pidea.is.internal=false" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value="runIde" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+  </configuration>
+</component>

buildSrc/src/main/kotlin/intellijDependencies.kt

@@ -147,7 +147,6 @@ fun Project.runIdeTask(name: String, ideaPluginDir: File, ideaSandboxDir: File,
             "-XX:ReservedCodeCacheSize=240m",
             "-XX:+HeapDumpOnOutOfMemoryError",
             "-ea",
-            "-Didea.is.internal=true",
             "-Didea.debug.mode=true",
             "-Didea.system.path=$ideaSandboxDir",
             "-Didea.config.path=$ideaSandboxConfigDir",
@@ -165,6 +164,8 @@ fun Project.runIdeTask(name: String, ideaPluginDir: File, ideaSandboxDir: File,
             jvmArgs("-Didea.ProcessCanceledException=disabled")
         }
 
+        jvmArgs("-Didea.is.internal=${project.findProperty("idea.is.internal") ?: true}")
+
         project.findProperty("idea.args")?.let { arguments ->
             jvmArgs(arguments.toString().split(" "))
         }