Legal API: should provide decoded submitter name for bootstrap filing

When the entity is a business, items in the ledger (which are provided by the `get filings` endpoint) show the decoded submitter ("filed by"):

However, when this is a bootstrap filing (IA, registration, amalgamation, and continuation in), the application filing (which is provided by the `get filing` endpoint) shows the coded (raw) submitter. (It doesn't matter if the user is staff or not.)

Examples:

and

This ticket is to request that the Legal API provide the decoded submitter name in the "get filing" response.