fix: suppress [object Object] defaults (probably Org flags)

[mshanemc]

@W-13215411@

#652 has the UT without the fix so you can prove the test is testing properly

[jshackell-sfdc]

QA:

• ✅ set global target-org config var, generated files shouldn't contain "Default value: [object Object]"?
• ✅ set local target-org config var, generated files shouldn't...
• ✅ set global target-dev-hub config var, generated files shouldn't...
• ✅ set local target-dev-hub config var, generated files shouldn't...
• ❌ generate full set of command reference files with both config vars set to something, then compare output to currently checked in files, they should be the same.
  - The DITA files for "org delete scratch" and "org delete sandbox" now include a default value for --target-org (the value of my target-org config var). They didn't before. These are the only commands that do this -- other commands, such as "project deploy start", omit the default value of --target-org, which is correct for the CLI Reference.

Second QA:

• ✅ set global target-org config var, generated files shouldn't contain "Default value: [object Object]"?
• ✅ set local target-org config var, generated files shouldn't...
• ✅ set global target-dev-hub config var, generated files shouldn't...
• ✅ set local target-dev-hub config var, generated files shouldn't...
• ✅ generate full set of command reference files with both config vars set to something, then compare output to currently checked in files, they should be the same.