add try catch to CLR Object Marshaler getStringValue

[mjkkirschner]

Purpose

Address the situation where a ToString call on a clr object that is not null results in an exception - it turns out this happens quite frequently in Autocad and Revit.

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

[aparajit-pratap]

@mjkkirschner can we verify that the ToString calls on these Revit/AutoCAD objects are throwing the exceptions and that they are the reason for the crash?

[mjkkirschner]

I can try to reproduce locally with Revit, but the stack trace seems to imply that:
#10816

[mjkkirschner]

crashed before - after seems to execute ok.

[aparajit-pratap]

@mjkkirschner it looks like the exception was occurring for only certain parameters and not all. In cases, where the exception is being thrown and caught, there should be empty strings, am I right?

[mjkkirschner]

yep!