Upgrade SSH.NET dependency from 2020.0.2 to 2024.2.0

[Piyush37-6]

Pull Request Description

1. What was there?

• Old State: The codebase referenced SSH.NET version 2020.0.2 (released in 2020) across three projects:
  1. MissionPlanner.csproj (with a legacy targetFramework="net40" parameter)
  2. MissionPlannerLib.csproj
  3. ExtLibs/solo/solo.csproj

2. Why was the old version bad?

• Security Risks: Version 2020.0.2 is missing key security fixes and patches that have been released over the past several years.
• Protocol Limitations: It does not natively support several newer secure SSH key exchange algorithms and cipher suites (such as modern Elliptic Curve or Ed25519 signatures) which are now standard on modern Linux/companion computer SSH servers.
• Legacy Targeting: The .csproj files contained legacy attributes like targetFramework="net40" inside NuGet package references, causing package restoration inefficiencies in modern build systems.

3. What has changed?

• Upgraded the package version of SSH.NET to 2024.2.0 in all three .csproj files.
• Cleaned up the metadata parameter in MissionPlanner.csproj by removing the outdated targetFramework="net40" attribute.

4. What is improved / Why is the new version good?

• Modern Cryptographic Compatibility: Provides out-of-the-box support for newer SSH key types and cipher algorithms, making connections to modern Linux/Edison/Solo companion computers more robust and secure.
• Performance Enhancements: Contains optimized cryptographic routines and connection stability improvements.
• Security Hardening: Patches old vulnerabilities present in the 2020 release.
• Cleaned SDK-style Project Files: Streamlines package resolution for developers building with modern Visual Studio (VS 2022+).