Added LED Brightness Adjust (#4105)

* Added LED Brightness Adjust

Added a brightness adjustment to allow an aux channel to change brightness.

Tested with SpeedyBeeF7V3. Needs Language Pack Added.

* Update src/js/tabs/adjustments.js

---------

Co-authored-by: Mark Haslinghuis <[email protected]>

Author: jpmreece

locales/en/messages.json

@@ -2717,6 +2717,9 @@
     },
     "adjustmentsFunction30": {
         "message": "LED Profile Selection"
+    },
+	"adjustmentsFunction31": {
+        "message": "LED Brightness Adjust"
     },
     "adjustmentsSave": {
         "message": "Save"

src/js/tabs/adjustments.js

@@ -272,7 +272,7 @@ adjustments.cleanup = function (callback) {
 
 adjustments.adjust_template = function () {
     const selectFunction = $('#functionSelectionSelect');
-    const elementsNumber = 31; // 'LED Profile Select' are the last adjustmentsFunction
+    const elementsNumber = 32; // 'LED Dimmer' is the last adjustmentsFunction
 
     for (let i = 0; i < elementsNumber; i++) {
         selectFunction.append(new Option(i18n.getMessage(`adjustmentsFunction${i}`), i));