message: Don't depend on the `modifyMtime` task if it has not been registered
  When registering the Cargo commands tasks. The `aws:sdk` is the only
  Gradle subproject that depends on the Cargo commands tasks, but that
  does not register the `modifyMtime` task.
  Partially addresses
diff: @@ -215,27 +215,33 @@ fun Project.registerCargoCommandsTasks(
  outputDir: File,
  defaultRustDocFlags: String,
  ) {
  + val dependentTasks =
  + listOfNotNull(
  + "assemble",
  + "generateCargoConfigToml",
  + this.tasks.findByName("modifyMtime")?.let { "modifyMtime" },
  + )
  this.tasks.register<Exec>(Cargo.CHECK.toString) {
  - dependsOn("assemble", "modifyMtime", "generateCargoConfigToml")
  + dependsOn(dependentTasks)
  workingDir(outputDir)
  commandLine("cargo", "check", "--lib", "--tests", "--benches")
  }
  this.tasks.register<Exec>(Cargo.TEST.toString) {
  - dependsOn("assemble", "modifyMtime", "generateCargoConfigToml")
  + dependsOn(dependentTasks)
  workingDir(outputDir)
  commandLine("cargo", "test")
  }
  this.tasks.register<Exec>(Cargo.DOCS.toString) {
  - dependsOn("assemble", "modifyMtime", "generateCargoConfigToml")
  + dependsOn(dependentTasks)
  workingDir(outputDir)
  environment("RUSTDOCFLAGS", defaultRustDocFlags)
  commandLine("cargo", "doc", "--no-deps", "--document-private-items")
  }
  this.tasks.register<Exec>(Cargo.CLIPPY.toString) {
  - dependsOn("assemble", "modifyMtime", "generateCargoConfigToml")
  + dependsOn(dependentTasks)
  workingDir(outputDir)
  commandLine("cargo", "clippy")
  }
  