Polish "Only set imagePlatform if it has text"

See gh-43424

Author: mhalbritter

Diff for: spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/Image.java

@@ -295,7 +295,7 @@ private BuildRequest customize(BuildRequest request) {
 		if (StringUtils.hasText(this.applicationDirectory)) {
 			request = request.withApplicationDirectory(this.applicationDirectory);
 		}
-		if (!CollectionUtils.isEmpty(this.securityOptions)) {
+		if (this.securityOptions != null) {
 			request = request.withSecurityOptions(this.securityOptions);
 		}
 		if (StringUtils.hasText(this.imagePlatform)) {

Diff for: spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/ImageTests.java

@@ -49,6 +49,7 @@
  * @author Scott Frederick
  * @author Jeroen Meijer
  * @author Rafael Ceccone
+ * @author Moritz Halbritter
  */
 class ImageTests {
 
@@ -290,6 +291,14 @@ void getBuildRequestWhenHasImagePlatformUsesImagePlatform() {
 		assertThat(request.getImagePlatform()).isEqualTo(ImagePlatform.of("linux/arm64"));
 	}
 
+	@Test
+	void getBuildRequestWhenImagePlatformIsEmptyDoesntSetImagePlatform() {
+		Image image = new Image();
+		image.imagePlatform = "";
+		BuildRequest request = image.getBuildRequest(createArtifact(), mockApplicationContent());
+		assertThat(request.getImagePlatform()).isNull();
+	}
+
 	private Artifact createArtifact() {
 		return new DefaultArtifact("com.example", "my-app", VersionRange.createFromVersion("0.0.1-SNAPSHOT"), "compile",
 				"jar", null, new DefaultArtifactHandler());