fix:ct/openwebui.sh adding progressbar and minimize service downtime

[jobben-2025]

✍️ Description

When running ‚update‘ command the ollama service is taken down and then the download runs eventually 'really long' (low speed internet/ollama server connection), this could lead to unnecessary user intervention or even wrongly re-installations.
At least the long service downtime might affect users during daytime.

🔗 Related Issue

Fixes #
Adding the curl progress bar using -# and not -s (silent); changing the order of the steps to first download the file and if file is present then taking down ollama service and doing the update procedure.

✅ Prerequisites (X in brackets)

• Self-review completed – Code follows project standards.
• Tested thoroughly – Changes work as expected.
• No security risks – No hardcoded secrets, unnecessary privilege escalations, or permission issues.
• syntax - Ran syntax and shellcheck.

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🛠️ Type of Change (X in brackets)

• 🐞 Bug fix – Resolves an issue without breaking functionality.
• ✨ New feature – Adds new, non-breaking functionality.
• 💥 Breaking change – Alters existing functionality in a way that may require updates.
• 🆕 New script – A fully functional and tested script or script set.
• 🌍 Website update – Changes to website-related JSON files or metadata.
• 🔧 Refactoring / Code Cleanup – Improves readability or maintainability without changing functionality.
• 📝 Documentation update – Changes to README, AppName.md, CONTRIBUTING.md, or other docs.

[jobben-2025]

Did a retest on another Proxmox instance and noticed the progress bar not working.
Found a typo, the small ‚s‘ in the curl command was silencing the progress bar.
Applied 2nd commit, now everything is working properly as described.

[MickLesk]

Like Our VMS -fS#L, but remove all comments and then it need to recheck, because the msg spinner can Break the `##### progress bar

[jobben-2025]

Applied your change to -fS#LO (O is required to obtain same filename in filesystem for download) and re-tested on Proxmox, update starts running the download now properly, also added newline character „\n“ before curl command to keep message displayed „Downloading Ollama v.xxxx“. All inline comments removed.