when loading python engines dynamically fail fast

[mjkkirschner]

Purpose

When attempting to load python engines dynamically - attempt to load top level dependencies of the assembly containing the PythonEngine so we fail fast in a controlled way (inside a try catch)

I verified this avoids the crash in DynamoRevit in 2.19.x so if we do a release there we can back port this change.

In addition these crashes no longer occur with the new packages (in old Dynamo versions) because .NetFramework4.8 cannot load the assembly load context types - so it fails even earlier when the extension Ready call is made so in either case partially working Python engines are no longer added to the AvailableEngines collection

Also updates MLC and System.Collections.Immutable packages to net8 versions.

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated
• This PR contains no files larger than 50 MB

Release Notes

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Reviewers

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[github-actions]

UI Smoke Tests

Test: success. 2 passed, 0 failed.
TestComplete Test Result
Workflow Run: UI Smoke Tests
Check: UI Smoke Tests - net8.0

[pinzart90]

why bump up the version ?
ANy issues compatibility issues with hosts ? Need to update licensing ?
Will it cause issues if we cherry pick this in 2.19.5 ?

[mjkkirschner]

1. why use an old version?
2. I don't think so, I can look at Revit, but I think aligning on the .net8 version makes the most sense and avoids conflicts with other packages, like meta data load context net8 and system collections immutable.
3. I don't think we should cherry pick this.

[mjkkirschner]

@pinzart90 WRT to licensing were your steps for regenerating the license sheets documented somewhere in the release process wiki? - I can't find them atm.

[mjkkirschner]

WRT Revit - they have removed their use of MLC - only RTF is using it currently.

[pinzart90]

Regarding the license, I was thinking we shoul just update the about box stuff. The dependency reports can be postponed

[pinzart90]

Lgtm

[pinzart90]

Should we specify this new requirement to the documentation somewhere ?

[mjkkirschner]

Should we specify this new requirement to the documentation somewhere ?

Hmm - I think anyone writing a PythonEngine would likely look at the base class they have to inherit from - so I will add a comment to that base class summary.