Can't create a 1GP manage package with a dependency on an unlocked (no namespaced) package (eg. other open-source packages such as UnofficialSF)

[mattmartin26]

Describe the bug
When running cci flow run ci_master --org packaging I received the the following error message, which might represent a fundamental issue with how #42 was solutioned (with dependency on other open-source components):

Malformed request https://rcav-dev-ed.my.salesforce.com/services/data/v50.0/tooling/sobjects/PackageInstallRequest/. Response content: [{'message': 'You cannot install an unlocked package without a namespace into an org with a namespace.', 'errorCode': 'FIELD_INTEGRITY_EXCEPTION', 'fields': []}]

See this Stack Exchange article for a potential explanation.

Additional context
The latest pull request (#47) includes a dependency on a couple UnofficialSF open-source components that do NOT have namespaces. The ci_master flow errored out on the second attempt to install those packages (package version id: 04t5G0000047xO4QAI). First package seems to have been successful (version id: 04t4W00000309DuQAI).