Use MuonIdHelperTool instead of single sub-helpers in MuonByteStreamCnvTest

Hi,

this MR exploits the MuonIdHelperTool in MuonByteStreamCnvTest instead of the single subhelpers.

For shifters/experts: There will be a dedicated MR by @pboescho soon which is migrating the MuonIdHelperTool and its usage in master homogeneously throughout the release. This MR is just needed for a larger one to come which manually sweeps the Run3 layout changes from 21.3 to master. Please let's not discuss the style how the ToolHandles are included here since the MR by @pboescho will re-iterate on this anyway soon.