Ledvance Planon lights: improvements based on feedback

- swap main and backlight switch bits.
- properly use standard color_temp dp as backup for dp 51 based color temp
- consistently use "std_" for standard dp prefixes
- set lower range of color temp to 3000K
- make backlight unavailable until dp 51 is received, as changing the color
  will give errors until then

std_rgbhsv is left for reference, even though it is unused by the actual
entities. Maybe one day the code will be able to use a different format dp
as a backup for a dp with multi-value format.

Issue #2683

custom_components/tuya_local/devices/ledvance_smart_plabl100x25b.yaml

@@ -19,7 +19,7 @@ entities:
         name: available
       - id: 51
         type: base64
-        mask: "000200000000000000000000"
+        mask: "000100000000000000000000"
         optional: true
         force: true
         name: switch
@@ -31,7 +31,7 @@ entities:
         optional: true
         name: work_mode
       - id: 22
-        name: standard_brightness
+        name: std_brightness
         type: integer
         range:
           min: 0
@@ -44,7 +44,7 @@ entities:
         name: brightness
         mapping:
           - dps_val: null
-            value_mirror: standard_brightness
+            value_mirror: std_brightness
         range:
           min: 0
           max: 1000
@@ -56,7 +56,7 @@ entities:
           max: 500
         mapping:
           - target_range:
-              min: 2700
+              min: 3000
               max: 6500
       - id: 51
         type: base64
@@ -66,9 +66,9 @@ entities:
         name: color_temp
         mapping:
           - dps_val: null
-            value_mirror: standard_brightness
+            value_mirror: std_color_temp
           - target_range:
-              min: 2700
+              min: 3000
               max: 6500
         range:
           min: 0
@@ -79,9 +79,16 @@ entities:
       - id: 20
         type: boolean
         name: available
+        mapping:
+          - dps_val: true
+            value: true
+            constraint: switch
+            conditions:
+              - dps_val: null
+                value: false
       - id: 51
         type: base64
-        mask: "000100000000000000000000"
+        mask: "000200000000000000000000"
         optional: true
         force: true
         name: switch