Buy - Suggested Amount Pills needs to fill the remaining space

### What is this about?

In the Buy flow, the suggested amount pills ($50, $100, etc.) are currently oddly spaced, which leaves plenty of room at the end. This can be updated to have the pills be evenly spaced.

### Scenario

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### Design

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### Technical Details

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### Threat Modeling Framework

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### Acceptance Criteria

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### Stakeholder review needed before the work gets merged

- [ ] 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

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