Add tests for commissionable node and dual (#8801)

* Add tests for commissionable node and dual

Moves some of the operational definitions into the anonymous
namespace so they can be shared among tests. Adds tests
for commissionable node, and node that is advertising two
operational fabrics and a commissionable node. This is required
in order to properly test mdns stop commands on minimal impl.

Also fix a weird bug in the advertiser where we bail early on
setting up the subtypes if we don't have a vendor ID. Not sure
where that came from, but it looks like something got misplaced
as we were refactoring.

* Remove debug line.

src/lib/mdns/Advertiser_ImplMinimalMdns.cpp

@@ -587,11 +587,6 @@ FullQName AdvertiserMinMdns::GetCommisioningTextEntries(const CommissionAdvertis
         snprintf(txtDiscriminator, sizeof(txtDiscriminator), "D=%d", params.GetLongDiscriminator());
         txtFields[numTxtFields++] = txtDiscriminator;
 
-        if (!params.GetVendorId().HasValue())
-        {
-            return allocator->AllocateQName(txtDiscriminator);
-        }
-
         char txtCommissioningMode[chip::Mdns::kKeyCommissioningModeMaxLength + 4];
         snprintf(txtCommissioningMode, sizeof(txtCommissioningMode), "CM=%d", params.GetCommissioningMode() ? 1 : 0);
         txtFields[numTxtFields++] = txtCommissioningMode;

src/lib/mdns/ServiceNaming.h

@@ -36,6 +36,7 @@ constexpr char kOperationalProtocol[]          = "_tcp";
 constexpr char kCommissionProtocol[]           = "_udp";
 constexpr char kLocalDomain[]                  = "local";
 constexpr size_t kOperationalServiceNamePrefix = 16 + 1 + 16; // 2 * 64-bit value in HEX + hyphen
+constexpr size_t kCommissionServiceNamePrefix  = 16;
 
 // each includes space for a null terminator, which becomes a . when the names are appended.
 constexpr size_t kMaxCommisisonableServiceNameSize =