[FEATURE REQUEST] UnigetUI checks for updates on start-up regardless of Update Frequency setting.

### Please confirm these before moving forward

- [x] I have searched for my issue and have not found a work-in-progress/duplicate/resolved issue.
- [x] I have tested that this issue has not been fixed in the latest [(beta or stable) release](https://github.com/marticliment/WingetUI/releases/).
- [x] I have checked the [FAQ](https://github.com/marticliment/WingetUI#frequently-asked-questions) section for solutions.
- [x] This issue is about a bug (if it is not, please use the [correct template](https://github.com/marticliment/WingetUI/issues/new/choose)).

### UniGetUI Version

3.2.0

### Windows version, edition, and architecture

Windows 10 Pro x64

### Describe your issue

UnigetUI checks for package updates on start-up, in my case presenting the user with installable updates generally at least once a day, often several times per day, which is what I was trying to avoid by setting the 'Check for Updates Every' setting to one week.

It looks like this setting assumes the computer runs permanently, however I would argue that most users shut their computers down between uses.

UnigetUI should have an option to not check for package updates on startup, or at the very least nerf the notification generated when it does.

The behaviour I expect is that once per week (e.g. the first start-up after 06:00am on Fridays), UnigetUI will notify me if there are updates to install.

### Steps to reproduce the issue

_No response_

### UniGetUI Log

```text
[16/05/2025 07:46:30] __ __ _ ______ __ __ ______
/ / / /___ (_) ____/__ / /_/ / / / _/
/ / / / __ \/ / / __/ _ \/ __/ / / // /
/ /_/ / / / / / /_/ / __/ /_/ /_/ // /
\____/_/ /_/_/\____/\___/\__/\____/___/
Welcome to UniGetUI Version 3.2.0
[16/05/2025 07:46:30]
[16/05/2025 07:46:30] Build 90
[16/05/2025 07:46:30] Encoding Code Page set to 437
```

### Package Managers Logs

```text
Manager WinGet with version:
System WinGet CLI Version: v1.10.340
Using Native WinGet helper (COM Api)
```

### Relevant information

_No response_

### Screenshots and videos

_No response_