Added Check for Import Errors When Running CREATE MODEL Statement

[MinuraPunchihewa]

Description

This PR adds a check for import errors when running CREATE MODEL statements and raises the relevant error. This is to avoid the TypeError: 'NoneType' object is not callable error being logged when running such statement typically fail.

Fixes #9018

Type of change

• 🐛 Bug fix (non-breaking change which fixes an issue)

Verification Process

To ensure the changes are working as expected:

• Test Location: Specify the URL or path for testing.
• Verification Steps: Outline the steps or queries needed to validate the change. Include any data, configurations, or actions required to reproduce or see the new functionality.

Additional Media:

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With this fix, the errors raised are now more precise and informative as shown below,

Note: I have introduced this error to the RAG handler temporarily for demonstration purposes.

Checklist:

• My code follows the style guidelines(PEP 8) of MindsDB.
• I have appropriately commented on my code, especially in complex areas.
• Necessary documentation updates are either made or tracked in issues - N/A.
• Relevant unit and integration tests are updated or added.