[Feature]: Make stacks transaction fee estimation more robust

[djordon]

Feature - Make stacks transaction fee estimation more robust

1. Description

We only have one source for expected fees for stacks transactions, which could potentially return weird estimates for the expected fees. This ticket is to have some safeguards in place for fee estimation.

Also, we need to figure out whether we should use the high or medium priority transaction fee estimates for sBTC related stacks transactions.

1.1 Context & Purpose

2. Technical Details:

2.1 Acceptance Criteria:

• Make the stacks transaction fee estimation code more robust.
• Maybe change to using the medium priority stacks transaction fee estimate.

3. Related Issues and Pull Requests (optional):

This came up in this discussion #361 (comment), which addressed #233.

[djordon]

Hmm, we probably want high priority for rotate-keys contract calls and medium (or maybe even low) priority for other transactions, like withdrawal-accept.