Project import fails with JetBrains Fleet

What happened?

When enabling Smart Mode with JetBrains Fleet, projects with this plugin applied fail due to the expectation that the .idea directory will exist:

java.io.FileNotFoundException: /home/coder/Projects/bb/edge/edgezuul/.idea/palantir-java-format.xml (No such file or directory)	
at com.google.common.io.Files.newWriter(Files.java:110)	
at com.palantir.javaformat.gradle.PalantirJavaFormatIdeaPlugin.updateIdeaXmlFile(PalantirJavaFormatIdeaPlugin.java:132)	
at com.palantir.javaformat.gradle.PalantirJavaFormatIdeaPlugin.createOrUpdateIdeaXmlFile(PalantirJavaFormatIdeaPlugin.java:108)	
at com.palantir.javaformat.gradle.PalantirJavaFormatIdeaPlugin.lambda$configureIntelliJImport$8(PalantirJavaFormatIdeaPlugin.java:87)	
at org.gradle.internal.code.DefaultUserCodeApplicationContext$CurrentApplication$1.execute(DefaultUserCodeApplicationContext.java:122)

That's not the case with Fleet, but it is technically an IntelliJ import because that's what the smart mode backend is hosting.

What did you want to happen?

Avoid failing when the .idea directory does not exist. Workaround is to mkdir .idea.

Start at PalantirJavaFormatIdeaPlugin.createOrUpdateIdeaXmlFile and updateIdeaXmlFile, where the stack trace shows the IntelliJ import setup attempts to write under .idea. Reproduce a Fleet Smart Mode import without an existing .idea directory and verify that the project import succeeds without requiring the mkdir workaround.