schemas: legacy: remove unused "Units" property

'Units' property is now no longer required as part of 'Aggregate'
schema.

Tested: Schema Validator Pass

Change-Id: I0fb90d70ba535565a237f80a187f1c6a4163fc93
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/schemas/legacy.json b/schemas/legacy.json
index c199817..4db3077 100644
--- a/schemas/legacy.json
+++ b/schemas/legacy.json
@@ -847,9 +847,6 @@
                 "MaxReading": {
                     "$ref": "#/$defs/Types/MaxReading"
                 },
-                "Units": {
-                    "$ref": "#/$defs/Types/Units"
-                },
                 "MinReading": {
                     "$ref": "#/$defs/Types/MinReading"
                 },