Revert "fix: capitalize scalar receipt header"

[gusinacio]

Reverts #126

As per HeaderName::from_static documentation https://docs.rs/http/latest/http/header/struct.HeaderName.html#method.from_static. This panics if it's not lowercase and gets into a poisoned state because of lazy_static! use

[coveralls]

Pull Request Test Coverage Report for Build 8098386871

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.05%) to 64.91%

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Files with Coverage Reduction	New Missed Lines	%
tap-agent/src/tap/sender_accounts_manager.rs	2	58.46%

Totals
Change from base Build 8097174113:	-0.05%
Covered Lines:	2845
Relevant Lines:	4383

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💛 - Coveralls