Remove IsTestProject from MTP doc page (#45175)

Author: Youssef1313

docs/core/testing/microsoft-testing-platform-integration-dotnet-test.md

@@ -41,7 +41,6 @@ By default, `dotnet test` is using VSTest behavior to run tests. You can enable
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
-    <IsTestProject>true</IsTestProject>
 
     <OutputType>Exe</OutputType>
     <EnableMSTestRunner>true</EnableMSTestRunner>
@@ -137,7 +136,6 @@ Or in project file:
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
-    <IsTestProject>true</IsTestProject>
 
     <OutputType>Exe</OutputType>
     <EnableMSTestRunner>true</EnableMSTestRunner>
@@ -179,7 +177,6 @@ Or in project file:
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
-    <IsTestProject>true</IsTestProject>
 
     <OutputType>Exe</OutputType>
     <EnableMSTestRunner>true</EnableMSTestRunner>