[convert2gamma] fix S1 GRD thermal noise removal

[johntruckenbrodt]

Back when the S1 GAMMA import functionality was developed, it was assumed in GAMMA that noise was already removed in GRDs and specifying the XML file meant adding it back to the data.
This had changed in July 2015 but pyroSAR never changed with it. Hence, thermal noise was not subtracted from the data on import.
This has now finally been discovered and fixed.

[coveralls]

Pull Request Test Coverage Report for Build 23494595113

Details

• 1 of 6 (16.67%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.04%) to 55.089%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pyroSAR/gamma/util.py	1	6	16.67%

Files with Coverage Reduction	New Missed Lines	%
pyroSAR/gamma/util.py	1	5.05%
pyroSAR/S1/auxil.py	1	42.27%

Totals
Change from base Build 22911083881:	-0.04%
Covered Lines:	4189
Relevant Lines:	7604

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💛 - Coveralls