Cannot Remove CPE from Component

### Current Behavior:
When I try to remove the CPE string from a component and click Update, I get an error (HTTP Bad Request [400]).

### Steps to Reproduce:
Add a CPE to a component, Update, and then try to remove it.

### Expected Behavior:
The CPE format validity check should allow empty strings.

### Environment:
- Dependency-Track Version: 3.7
- Distribution: Docker
- BOM Format & Version: N/A
- Database Server: N/A
- Browser: Chrome 104.0.5112.102

### Additional Details:
The CPE that was added to the wrong component has a vulnerability associated with it, so I'm not sure if this creates limitations on how that component can be edited.