Add option to disable GitHub job summary output in Octopus GitHub Actions

[tolga-definely]

We use OctopusDeploy/create-release-action@v4 and OctopusDeploy/deploy-release-action@v4 in GitHub Actions.

Today the actions write directly to the GitHub job summary. For example, in deploy-release-action:

const stepSummaryFile = process.env.GITHUB_STEP_SUMMARY
if (stepSummaryFile && deploymentResults.length > 0) {
  writeFileSync(stepSummaryFile, `🐙 Octopus Deploy queued deployment(s) in Project **${parameters.project}**.`)
}

There is currently no way for consumers to prevent these summaries from being generated.

This becomes very noisy when deploying multiple projects in one workflow. We already generate our own deployment summary, but it gets buried between the Octopus-generated summary entries.

Requested change:
Please add a supported opt-out, for example:

• an input like disable_job_summary: true, or
• an env flag like OCTOPUS_DISABLE_STEP_SUMMARY=true

Expected behavior:
When the opt-out is enabled, the action should skip writing to GITHUB_STEP_SUMMARY entirely.

Affected actions:

• OctopusDeploy/create-release-action
• OctopusDeploy/deploy-release-action