Bump OpenTelemetry to 1.6.0 #7146

Job	Run time
build / build (windows-2022, /c/ProgramData/OpenTelemetry .NET AutoInstrumentation/logs)	11m 56s
build / build (ubuntu-20.04, /var/log/opentelemetry/dotnet)	6m 57s
build / build (macos-11, /var/log/opentelemetry/dotnet)	11m 14s
build-container / build-container (alpine, linux-musl)	7m 0s
build-container / build-container (centos, linux-glibc)	6m 35s
test-build-container (alpine, alpine, linux-musl)	12m 1s
test-build-container (centos, centos, linux-glibc)	12m 31s
test-build-container (debian, centos, linux-glibc)	12m 31s
test-build-native (windows-2022)	10m 43s
test-build-managed (net7.0, windows-2022)	15m 55s
test-build-managed (net7.0, ubuntu-20.04)	9m 52s
test-build-managed (net7.0, macos-11)	13m 5s
test-build-managed (net6.0, windows-2022)	15m 39s
test-build-managed (net6.0, ubuntu-20.04)	10m 47s
test-build-managed (net6.0, macos-11)	12m 36s
test-build-managed (net462, windows-2022)	15m 10s
test-build-windows-container-tests (windows-2022, windows-only)	17m 27s
build-nuget-packages / build-nuget-packages	6m 19s
test-nuget-packages (ubuntu-20.04)	3m 19s
test-nuget-packages (macos-11)	6m 9s
test-nuget-packages (windows-2022)	6m 21s
	3h 44m 7s

Provide feedback