Bug #6958 Make sure encoding type is set when sending Request

Call setMethod() so Encoding Type is set.
add test
#6959 - adding assertion to the test (didn't include any before)
#6959 - fixed assertion (we are checking specifically for the encoding type)
#6959 - adding `@group` annotation to the newly introduced test
Merge branch 'hotfix/#6959-set-correct-encoding-in-http-client-when-sending'

Close #6959