Update MicrosoftIdentityModel and Abstractions versions (#3604)

Author: pmaytak

Directory.Build.props

@@ -82,9 +82,9 @@
   </PropertyGroup>
 
   <PropertyGroup Label="Common dependency versions">
-    <MicrosoftIdentityModelVersion Condition="'$(MicrosoftIdentityModelVersion)' == ''">8.14.0</MicrosoftIdentityModelVersion>
+    <MicrosoftIdentityModelVersion Condition="'$(MicrosoftIdentityModelVersion)' == ''">8.15.0</MicrosoftIdentityModelVersion>
     <MicrosoftIdentityClientVersion Condition="'$(MicrosoftIdentityClientVersion)' == ''">4.79.2</MicrosoftIdentityClientVersion>
-    <MicrosoftIdentityAbstractionsVersion Condition="'$(MicrosoftIdentityAbstractionsVersion)' == ''">9.5.0</MicrosoftIdentityAbstractionsVersion>
+    <MicrosoftIdentityAbstractionsVersion Condition="'$(MicrosoftIdentityAbstractionsVersion)' == ''">9.6.0</MicrosoftIdentityAbstractionsVersion>
     <FxCopAnalyzersVersion>3.3.0</FxCopAnalyzersVersion>
     <SystemTextEncodingsWebVersion>4.7.2</SystemTextEncodingsWebVersion>
     <AzureSecurityKeyVaultSecretsVersion>4.6.0</AzureSecurityKeyVaultSecretsVersion>