[Feature] Add config vars for conversions

[fivetran-catfritz]

To support dynamic enablement of conversion-related tables in Facebook Ads and Reddit Ads, we need to add configuration variables to the models and also the quickstart.yml files.

When the conversions staging models are disabled, the corresponding end models should still run by filling in NULL values for the conversion fields. This ensures compatibility with downstream rollup reporting models and prevents model breakages due to missing fields.

Facebook Ads:

• One variable that enables/disabled the following models:

source:

• basic_ad_actions
• basic_ad_action_values

transform

• int_facebook_ads__conversions
• facebook_ads__account_report
• facebook_ads__ad_report
• facebook_ads__ad_set_report
• facebook_ads__campaign_report
• facebook_ads__url_report

Reddit Ads:

• It is probably more straightforward to also use one variable here, but one corresponding to each source could also be used.

source:

• account_conversions_report
• ad_group_conversions_report
• ad_conversions_report
• campaign_conversions_report

transform:

• reddit_ads__account_report
• reddit_ads__ad_group_report
• reddit_ads__ad_report
• reddit_ads__campaign_report
• reddit_ads__url_report

[LewisDavies]

I had an issue with dbt Fusion that @fivetran-avinash suggested would be relevant here (link to the original thread in dbt Slack)

I use the ad reporting package and I'm getting an error with Fusion because a source table doesn't exist:

error: dbt1053: Node 'source.facebook_ads_source.facebook_ads.basic_ad_action_values' not available; build it first (cache at: db/schemas/FIVETRAN_DATABASE/FACEBOOK_ADS/basic_ad_action_values)

The table is enabled in Fivetran but it hasn't been created in our warehouse, presumably because we don't have any data to export (and I don't know enough about Facebook Ads to understand why). Setting +static_analysis: off prevented another error but I can't make the one above go away.
I was considering creating an empty table with the appropriate columns myself. Is there a better way to address this?