Update GitHub Actions workflows to reflect repository ownership change

[abruneau]

• Updated repository references in build-images.yml, nightly-release.yml, and release.yml from 'open-telemetry/opentelemetry-demo' to 'tsuga-dev/opentelemetry-demo'.
• Changed default GHCR repository in component-build-images.yml from 'ghcr.io/open-telemetry/demo' to 'ghcr.io/tsuga-dev/otel-demo'.
• Added conditional check for repository in fossa.yml to match the new repository name.

Changes

Please provide a brief description of the changes here.

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

• ❌ - login: @abruneau / name: Antonin Bruneau . The commit (29d6b1a) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.