refactor: improve logs and add exception stack trace for YarnAuditAnalyzer (#7694)

Author: nhumblot

core/src/main/java/org/owasp/dependencycheck/analyzer/NodePackageAnalyzer.java

@@ -196,7 +196,8 @@ private boolean isNodeAuditEnabled(Engine engine) {
                     try {
                         ((AbstractNpmAnalyzer) a).prepareFileTypeAnalyzer(engine);
                     } catch (InitializationException ex) {
-                        LOGGER.debug("Error initializing the {}", a.getName());
+                        String message = "Error initializing the " + a.getName();
+                        LOGGER.debug(message, ex);
                     }
                 }
                 return a.isEnabled();

core/src/main/java/org/owasp/dependencycheck/analyzer/YarnAuditAnalyzer.java

@@ -188,12 +188,14 @@ protected void prepareFileTypeAnalyzer(Engine engine) throws InitializationExcep
                     case yarnExecutableNotFoundExitValue:
                     default:
                         this.setEnabled(false);
-                        LOGGER.warn("The {} has been disabled. Yarn executable was not found.", getName());
+                        LOGGER.warn("The {} has been disabled after receiving exit value {}. Yarn executable was not " +
+                                        "found or received a non-zero exit value.", getName(), exitValue);
                 }
             }
         } catch (Exception ex) {
             this.setEnabled(false);
-            LOGGER.warn("The {} has been disabled. Yarn executable was not found.", getName());
+            LOGGER.warn("The {} has been disabled after receiving an exception. This can occur when Yarn executable " +
+                    "is not found.", getName());
             throw new InitializationException("Unable to read yarn audit output.", ex);
         }
     }