Align spring.flyway.execute-in-transaction property with Flyway default

See gh-35447

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayProperties.java

@@ -365,7 +365,7 @@ public class FlywayProperties {
 	/**
 	 * Whether Flyway should execute SQL within a transaction.
 	 */
-	private boolean executeInTransaction;
+	private boolean executeInTransaction = true;
 
 	public boolean isEnabled() {
 		return this.enabled;

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/flyway/FlywayPropertiesTests.java

@@ -92,6 +92,7 @@ class FlywayPropertiesTests {
 		assertThat(properties.getPlaceholderSeparator()).isEqualTo(configuration.getPlaceholderSeparator());
 		assertThat(properties.getScriptPlaceholderPrefix()).isEqualTo(configuration.getScriptPlaceholderPrefix());
 		assertThat(properties.getScriptPlaceholderSuffix()).isEqualTo(configuration.getScriptPlaceholderSuffix());
+		assertThat(properties.isExecuteInTransaction()).isEqualTo(configuration.isExecuteInTransaction());
 	}
 
 	@Test