Ticket8671 Give a better error when cache is corrupt

[LilithCole]

Description of work

Simple catch to make a more verbose error.

To test

Ticket8671

Acceptance criteria

• Delete C:\Users<user>.cache\pyright-python\nodeenv\Scripts
• On main, try to load any script, it should have an unhelpful json error
• On this branch, it will tell you what to do
• Follow the prompts instructions, the script should now load

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Code Review

• Is the code of an acceptable quality?
• Are there unit tests in place? Are the unit tests small and test the a class in isolation?
• Have the changes been documented in the release notes. If so, do they describe the changes appropriately?

Functional Tests

• Do changes function as described? Add comments below that describe the tests performed.
• How do the changes handle unexpected situations, e.g. bad input?
• Has developer documentation been updated if required?