[MNG-6829] Replace StringUtils#isEmpty(String) & #isNotEmpty(String) (#79)

* [MNG-6829] Replace StringUtils#isEmpty(String) & #isNotEmpty(String)

Last batch of is(Not)Empty for https://issues.apache.org/jira/browse/MNG-6829
These are the smallest change sets, hence why I opened more at the same time.
After this we can target the next most often used method from the StringUtils classes.


Use this link to re-run the recipe: https://public.moderne.io/recipes/org.openrewrite.java.migrate.apache.commons.lang.IsNotEmptyToJdk?organizationId=QXBhY2hlIE1hdmVu

Co-authored-by: Moderne <team@moderne.io>

* Checkstyle

---------

Co-authored-by: Moderne <team@moderne.io>
diff --git a/src/main/java/org/apache/maven/shared/verifier/Verifier.java b/src/main/java/org/apache/maven/shared/verifier/Verifier.java
index 752fdc8..3c2b68e 100644
--- a/src/main/java/org/apache/maven/shared/verifier/Verifier.java
+++ b/src/main/java/org/apache/maven/shared/verifier/Verifier.java
@@ -425,7 +425,7 @@
     {
         File file = new File( getBasedir(), filename );
 
-        if ( StringUtils.isNotEmpty( encoding ) )
+        if ( encoding != null && !encoding.isEmpty() )
         {
             return Files.newBufferedReader( file.toPath(), Charset.forName( encoding ) );
         }
@@ -1396,7 +1396,7 @@
     {
         if ( embeddedLauncher == null )
         {
-            if ( StringUtils.isEmpty( mavenHome ) )
+            if ( mavenHome == null || mavenHome.isEmpty() )
             {
                 embeddedLauncher = Embedded3xLauncher.createFromClasspath();
             }
@@ -1761,7 +1761,7 @@
      */
     public void setLogFileName( String logFileName )
     {
-        if ( StringUtils.isEmpty( logFileName ) )
+        if ( logFileName == null || logFileName.isEmpty() )
         {
             throw new IllegalArgumentException( "log file name unspecified" );
         }
@@ -1861,7 +1861,7 @@
 
     private void setForkMode()
     {
-        if ( StringUtils.isEmpty( mavenHome ) && StringUtils.isEmpty( forkMode ) )
+        if ( ( mavenHome == null || mavenHome.isEmpty() ) && ( forkMode == null || forkMode.isEmpty() ) )
         {
             forkMode = "auto";
         }