[ReleasePR appplatform] feat: fix build agent pool swagger (#2115)

Create to sync Azure/azure-rest-api-specs#17185
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/appplatform?expand=1)

Author: msftbot[bot]

schemas/2022-01-01-preview/Microsoft.AppPlatform.json

@@ -494,6 +494,28 @@
           "type": "string",
           "description": "The name of the build service agent pool resource."
         },
+        "properties": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/BuildServiceAgentPoolProperties"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Build service agent pool properties"
+        },
+        "systemData": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/SystemData"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Metadata pertaining to creation and last modification of the resource."
+        },
         "type": {
           "type": "string",
           "enum": [
@@ -504,6 +526,7 @@
       "required": [
         "apiVersion",
         "name",
+        "properties",
         "type"
       ],
       "description": "Microsoft.AppPlatform/Spring/buildServices/agentPools"
@@ -1582,6 +1605,33 @@
       ],
       "description": "Reference to a build result"
     },
+    "BuildServiceAgentPoolProperties": {
+      "type": "object",
+      "properties": {
+        "poolSize": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/BuildServiceAgentPoolSizeProperties"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Build service agent pool size properties"
+        }
+      },
+      "description": "Build service agent pool properties"
+    },
+    "BuildServiceAgentPoolSizeProperties": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "type": "string",
+          "description": "The name of build service agent pool size"
+        }
+      },
+      "description": "Build service agent pool size properties"
+    },
     "CertificateProperties": {
       "type": "object",
       "oneOf": [