Backport of Return instead of panic in code that is only used in dev into release/0.6.x

[hc-github-team-waypoint]

Backport

This PR is auto-generated from #2533 to be assessed for backporting due to the inclusion of the label backport/0.6.x.

The below text is copied from the body of the original PR.

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This bit of code causes an issue in at least AWS ECS server installs using on-demand runners, where a release will fail:

! Unrecognized remote plugin message:
  This usually means that the plugin is either invalid or simply
  needs to be recompiled to support the latest protocol.

The underlying issue is a panic during the init phase caused by something that's only used in development, so here we change that to simply return.

UPDATE: refactored/rebased to completely exclude internal/assets/dev.go from builds with the assetsembedded tag (see the Makefile for reference). The dev.go file was generating dev_assets.go which was not included in builds, however the dev.go file itself still was, and it's init() method could cause troubles