DRIP setting on Broker accounts

Broker API

Adds a drip setting to Broker accounts for dividend reinvestment.

• drip.equities_dividend_reinvestments is accepted on account creation and account updates. Omit drip to leave the current setting unchanged.
• drip is returned on the account response once DRIP has been enabled at least once.
• Enabling DRIP requires a signed customer agreement at the required revision, either already on the account or submitted in the same request; otherwise the request returns HTTP 422.
• Enabling DRIP on donor_advised, trust, omnibus_sub, and omnibus_non_disclosed accounts returns HTTP 422. Disabling it is accepted.
• This feature is available in sandbox for beta partners only.

Affected Endpoints

• POST /v1/accounts
• PATCH /v1/accounts/{account_id}
• GET /v1/accounts
• GET /v1/accounts/{account_id}