Send maximum amount feature not functioning fully.

### What is this about?

When wanting to send all of the crypto of a token: the send maximum amount button ( "Max" ) exists.
It only appears when there are no tokens for a coin.

When there are tokens loaded in a coin, as shown in screenshot for btc, the user has to manually input the decimal amount without the use ( "Max" ) button.

This button has always been there in metamask wallets, transactions are jarring without it.
Issue in Firefox Browser

### 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

Start by tracing the send flow and the Max button behavior shown in the attached screenshots, comparing coins with no tokens against coins with loaded tokens. Reproduce the issue in Firefox and verify that the maximum amount can be selected in both cases without requiring manual decimal entry.

Written by the indexing model from the issue text.