transaction-utils determineTransactionType does not handle missing `to` parameter

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### What is this about?

The `readAddressAsContract` function accepts an input parameter address as `string`.
The `determineTransactionTypes` function calls this with potentially undefined `to`.

### Scenario

_No response_

### Design

_No response_

### Technical Details

Either:
- Handle the case explicitly
- Perform input validation and throw explicit error

### Threat Modeling Framework

_No response_

### Acceptance Criteria

_No response_

### Stakeholder review needed before the work gets merged

- [X] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

https://github.com/MetaMask/metamask-extension/pull/23276/files#diff-04988d119dcfa22dc14a7fef5eeb754d471a03dfe927809c2e1b15c3e8fa2d5aR145

Start by inspecting the referenced pull request diff, then trace determineTransactionTypes and readAddressAsContract to understand how an undefined to value reaches the string parameter. Review the relevant transaction utility tests, if present, and verify that the chosen handling is covered without breaking existing transaction-type behavior.

Written by the indexing model from the issue text.