Update System.Formats.Asn1.csproj (#106324)

* Update System.Formats.Asn1.csproj

Now that the project has a package README, the opt-out switch isn't required anymore. Also, remove the commonly used types section in favor of the package readme from the package description.

* Update System.Formats.Asn1.csproj

src/libraries/System.Formats.Asn1/src/System.Formats.Asn1.csproj

@@ -6,13 +6,7 @@
     <DefineConstants>$(DefineConstants);CP_NO_ZEROMEMORY</DefineConstants>
     <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
     <IsPackable>true</IsPackable>
-    <PackageDescription>Provides classes that can read and write the ASN.1 BER, CER, and DER data formats.
-
-Commonly Used Types:
-System.Formats.Asn1.AsnReader
-System.Formats.Asn1.AsnWriter</PackageDescription>
-    <!-- TODO: Add package README file: https://github.com/dotnet/runtime/issues/99358 -->
-    <EnableDefaultPackageReadmeFile>false</EnableDefaultPackageReadmeFile>
+    <PackageDescription>Provides classes that can read and write the ASN.1 BER, CER, and DER data formats.</PackageDescription>
   </PropertyGroup>
 
   <ItemGroup>