Migrate to getsentry/cli

### Description

https://github.com/getsentry/sentry-cli will be deprecated in favor of https://github.com/getsentry/cli

The new CLI (version 4.0) and is meant as drop-in replacement, however this needs to be checked and there are some migration steps to be aware of.

sentry-dotnet downloads one hash-pinned binary for the build host.

* debug-files upload, debug-files bundle-sources, and info --no-defaults exist.
* upload-proguard is now proguard upload.
* releases new is now release create.
* releases set-commits is now release set-commits; core modes such as --auto, --local, --clear, --commit, and --initial-depth exist.
* The new CLI has no command-line --auth-token or --url flags; it expects SENTRY_AUTH_TOKEN and SENTRY_URL. The MSBuild target currently passes both as CLI arguments.

Risk: medium. MSBuild commands and credential handling must change. New CLI platform coverage must also match the .NET targets.

Start by locating the MSBuild target that downloads and invokes the hash-pinned sentry CLI binary, then compare its commands and credential arguments with getsentry/cli 4.0. Check platform coverage for the .NET targets and verify the listed debug-files, ProGuard, release, SENTRY_AUTH_TOKEN, and SENTRY_URL behavior. Done means the migration works across supported build hosts without command or credential regressions.

Written by the indexing model from the issue text.