Remove 'signature' parameter from *ContextMetadata

Author: julianna-ciq

packages/fdc3-schema/schemas/api/api.schema.json

@@ -288,9 +288,6 @@
             "title": "AppProvidableContextMetadata",
             "type": "object",
             "properties": {
-                "signature": {
-                    "type": "string"
-                },
                 "traceId": {
                     "type": "string"
                 }
@@ -302,9 +299,6 @@
             "title": "DesktopAgentProvidableContextMetadata",
             "type": "object",
             "properties": {
-                "signature": {
-                    "type": "string"
-                },
                 "traceId": {
                     "type": "string"
                 },