fix: Remove "The slug {Slug} did not match any of your Octopus Feature Toggles" log message when evaluating a toggle

[borland]

Background

OctopusFeatureContext logged a warning message when a toggle was evaluated but no definition could be found from the toggle provider.

This happens when a developer creates a new toggle in code, but doesn't go into Octopus Deploy and define the toggle. The library is attempting to warn about the missing configuration.

Discussion

If a toggle is being used for staged rollout, or other gradual introduction of a new feature, the logged warning can be useful.
However, another use-case for toggles is as escape hatches. My team does this quite often.

• We'll introduce a code change that we are 99% confident is fine
• We want this code change to be enabled by default, as the new software version rolls out
• We'll create a toggle which restores the old code path, to cover the 1%. Our expectation is that we'll never use this toggle, and needing to go into Deploy and define it (and then also clean it up when we clean up the toggle) is a papercut-style tax that it would be nice to avoid.

Results

Removes the logging.

OctopusFeatureContext returns a ResolutionDetails with an error message which conveys the same information to the user that the log did, so there is no loss in functionality.