Update azure-typespec/http-client-csharp-mgmt version to prerelease 1.0.0-alpha.20260811.2 - #61962

Update azure-typespec/http-client-csharp-mgmt version to prerelease 1.0.0-alpha.20260811.2#61962

azure-sdk-automation[bot] wants to merge 21 commits into

mainAzure/azure-sdk-for-net:mainfrom

validate-typespec-20260811.2-azure-typespec/http-client-csharp-mgmtAzure/azure-sdk-for-net:validate-typespec-20260811.2-azure-typespec/http-client-csharp-mgmtCopy head branch name to clipboard