UIEXT-3150: Remove misleading warning

* This warning was visible when legacy credentials were migrated upon
  showing the password widget. However, it is not useful to the user.

UIEXT-3150 (WebUI-Migration Excel Reader)

Author: tom-mi

org.knime.core.ui.tests/src/eclipse/org/knime/core/webui/node/dialog/defaultdialog/DefaultNodeDialogTest.java

@@ -774,11 +774,9 @@ void testApplyDataWithInvalidSettingsButValidFlowVariables() throws IOException,
                     b -> b.withControllingFlowVariableName(validFlowVariable.getName()).build())//
                 .build();
 
-            final var response = callApplyData(applyData);
+            callApplyData(applyData);
 
             assertFalse(m_nnc.getNodeContainerState().isExecuted()); // i.e. applied
-            assertThatJson(response).inPath("$.warningMessages[0]").isString()
-                .contains("settings overridden by flow variables have been saved as underlying manual settings");
         }
 
         @Test

org.knime.core.ui/src/eclipse/org/knime/core/webui/node/dialog/internal/SettingsApplier.java

@@ -304,9 +304,6 @@ private static void overwriteSettingsToMakeThemValid(final SettingsType settings
                 "The %s could not be applied since both underlying manual and overwritten flow variable settings are invalid: %s",
                 settingsDescription, ex.getMessage()), ex);
         }
-        DataServiceContext.get()
-            .addWarningMessage("The settings overridden by flow variables have been saved as underlying manual settings"
-                + " to prevent an invalid settings exception if flow variables are unset.");
     }
 
     private static Object getSettingsDescription(final SettingsType settingsType) {