fix(builder): fix flashbots auth signature

[dancoombs]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.

Project coverage is 58.68%. Comparing base (da102ee) to head (8feca7b).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/builder/src/sender/flashbots.rs	0.00%	9 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
crates/builder/src/sender/flashbots.rs	0.00% <0.00%> (ø)

Flag	Coverage Δ
unit-tests	58.68% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
rundler binary	0.00% <ø> (ø)
builder	62.97% <0.00%> (-0.05%)	⬇️
dev	∅ <ø> (∅)
pool	66.74% <ø> (ø)
provider	20.84% <ø> (ø)
rpc	25.87% <ø> (ø)
sim	76.76% <ø> (ø)
tasks	∅ <ø> (∅)
types	67.83% <ø> (ø)
utils	29.38% <ø> (ø)

[0xfourzerofour]

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