Minor MEV capture hook refactor

[jubeira]

Description

Minor refactor:

• isMevTaxExempt --> isMevTaxExemptSender for consistency
• Some < --> <= changes. Doesn't really affect the code because in the edges the fee increment is 0, so it's just returning earlier with the same result.

Type of change

• Bug fix
• New feature
• Breaking change
• Dependency changes
• Code refactor / cleanup
• Optimization: [ ] gas / [ ] bytecode
• Documentation or wording changes
• Other

Checklist:

• The diff is legible and has no extraneous changes
• Complex code has been commented, including external interfaces
• Tests have 100% code coverage
• The base branch is either main, or there's a description of how to merge

Issue Resolution

N/A

[elshan-eth]

One test is down but other things LGTM

[EndymionJkb]

Looks fine. Did they ask for the <= changes? The failing test seems unrelated. Did something change in the environment to make us start having these intermittent failures now? Add this to the list?