chore(ci): fix upload of benchmark results on master

[TomAFrench]

Description

Problem*

Resolves

Summary*

The filter which prevented attempting a benchmark upload on external PRs was also blocking uploads on master so these benchmarks weren't being updated.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.