* .NET & python SDKs parity for bad pulumi versions
They handle invalid Pulumi CLI version gracefully.
* Make python version property lazy
* Clarify .NET logic
* Add python test for validate_pulumi_version
* Add tests for invalid versions
* Fix python test
* Fix typo
* Fix tests
* Have _validate_pulumi_version handle parsing
* Modify python and .NET to parseAndValidate
* Modify typescript and go to parseAndValidate
* fix name