Rare flaky process_crash_monitoring failure

### Description

See the following log: https://github.com/eclipse-score/lifecycle/actions/runs/33185230202/job/98896390230?pr=564

### Analysis results

It looks like this is caused by the transition to the fallback run target getting cancelled by the control client with the request for the off run target. The control client requests a transition to the off target as soon as it detects the fallback file. In rare cases, it can detect this before the fallback run target activation has completed.

### Solution

There are a few potential ways to solve this:
- Decrease the frequency of the checks for the fallback file - less likely to detect it instantly
- Handle the case where the fallback transition is cancelled - why does this fail the test?
- Remove the request for the off state entirely and make the control client self terminate - is the test still valid without this?

### Error Occurrence Rate

Sporadic

### How to reproduce

The failure is very rare, and may not appear even after 600 runs

### Supporting Information

_No response_

### Classification

Minor

### First Affected Release

not released (main)

### Last Affected Release

not released (main)

### Expected Fixed Release

before release (main)

### Category

- [ ] Safety Relevant
- [ ] Security Relevant

Start with the linked GitHub Actions log for the process_crash_monitoring failure, then trace the fallback-file detection and control-client transition handling described in the analysis. Compare the three proposed approaches and determine why cancellation fails the test; done means the sporadic failure is resolved and the relevant test remains valid.

Written by the indexing model from the issue text.