[Bug] update date_spine model to accommodate empty `stripe__balance_transactions`

[fivetran-jamie]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the issue

Same issue as https://github.com/fivetran/dbt_quickbooks/issues/118

We need to add coalesces both the first_date and last_date to ensure the spine is not working with Nonetype values.

Relevant error log or model output

Database Error in model int_stripe__date_spine (models/intermediate/int_stripe__date_spine.sql)

Invalid datetime string "None"

Expected behavior

Date spine and its downstream models should not fail

the daily overview model includes non-balance-transaction data so it's still valuable to have even with no balance transaction records

dbt Project configurations

na

Package versions

na

What database are you using dbt with?

postgres, redshift, snowflake, bigquery, databricks

dbt Version

na

Additional Context

No response

Are you willing to open a PR to help address this issue?

• [X] Yes.
• [ ] Yes, but I will need assistance and will schedule time during our office hours for guidance
• [ ] No.