Bump vaadin.version from 24.3.8 to 24.3.9

Bumps `vaadin.version` from 24.3.8 to 24.3.9.

Updates `com.vaadin:vaadin-bom` from 24.3.8 to 24.3.9

Updates `com.vaadin:vaadin-maven-plugin` from 24.3.8 to 24.3.9

---
updated-dependencies:
- dependency-name: com.vaadin:vaadin-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: com.vaadin:vaadin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -16,7 +16,7 @@
     <description>Imports MT940 or Hibiscus data via REST and generates Optigem postings via rules or manually.</description>
     <properties>
         <java.version>21</java.version>
-        <vaadin.version>24.3.8</vaadin.version>
+        <vaadin.version>24.3.9</vaadin.version>
         <gson.version>2.10.1</gson.version>
         <gson-javatime-serialisers.version>1.1.2</gson-javatime-serialisers.version>
         <commons-io.version>2.16.0</commons-io.version>