Fix verification results (one api scheduled for removal)

[bric3]

• [x] Replace by JBColor.isBright() Excalidraw Integration 0.4.0 uses API scheduled for removal in future releases

  UIUtil.isUnderDarcula() (scheduled for removal in a future release) Deprecated method UIUtil.isUnderDarcula() is invoked in ExcalidrawEditor.uiThemeFromConfig(). This method will be removed in a future release

• [ ] Replace by FileDocumentManagerListener.TOPIC (in 2023.3) Since 2023.3 Excalidraw Integration 0.4.0 uses deprecated API, which may be removed in future releases leading to binary and source code incompatibilities

  AppTopics.FILE_DOCUMENT_SYNC Deprecated field AppTopics.FILE_DOCUMENT_SYNC is accessed in ExcalidrawEditor.<init>(Project, VirtualFile)

• [ ] Dependencies of Excalidraw Integration 0.4.0 specified in plugin.xml are resolved with respect to IntelliJ IDEA Ultimate IU-241.8102.112. Java 17.0.9 was used for verification.

  com.github.bric3.excalidraw 0.4.0
  \--- com.intellij 241.8102.112 [declaring module com.intellij.modules.platform]