Added a workaround for the mutability of native headers (#1323)

Since for some reason, the native headers sometimes are immutable even though the accessor says that the headers are mutable, then we have to ensure their
	 * mutability. We do so by first making a mutable copy of the native headers, then by removing the native headers from the headers map and replacing them with a mutable copy

fixes #1184

src/checkstyle/checkstyle-suppressions.xml

@@ -3,6 +3,7 @@
 	"-//Puppy Crawl//DTD Suppressions 1.1//EN"
 	"https://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
 <suppressions>
+	<suppress files=".*/test/.*" checks="JavadocVariable"/>
 	<suppress files=".*FinishedSpanHandlerTests.*" checks="LineLengthCheck"/>
 	<suppress files=".*GrpcTracingIntegrationTests.*" checks="LineLengthCheck"/>
 	<suppress files=".*IgnoreAutoConfiguredSkipPatternsIntegrationTests.*" checks="LineLengthCheck"/>