[VCN21] Do not add NOT_VCN_MANAGED capability if specifier is present

Test: atest NetworkRequestTest#testBypassingVcn
Fix: 176939355
Fix: 188597540
Merged-In: I98dd3f4652dc067eb5c4666e952db6c854bcbb10
Change-Id: I98dd3f4652dc067eb5c4666e952db6c854bcbb10
  (cherry-picked from aosp/1705390)
1 file changed