[YAML] Remove GetUniqueDiscriminator since cross-talks seems to be gone now

src/app/tests/suites/TestDiscovery.yaml

@@ -19,7 +19,7 @@ config:
     endpoint: 0
     discriminator:
         type: INT16U
-        defaultValue: GetUniqueDiscriminator()
+        defaultValue: 3840
     vendorId:
         type: INT16U
         defaultValue: 65521

src/app/tests/suites/commands/discovery/DiscoveryCommands.cpp

@@ -20,7 +20,6 @@
 
 #include <lib/support/SafeInt.h>
 #include <platform/CHIPDeviceLayer.h>
-#include <random>
 
 CHIP_ERROR DiscoveryCommands::FindCommissionable()
 {
@@ -114,36 +113,12 @@ CHIP_ERROR DiscoveryCommands::TearDownDiscoveryCommands()
     return CHIP_NO_ERROR;
 }
 
-uint16_t DiscoveryCommands::GetUniqueDiscriminator()
-{
-    if (mDiscriminatorUseForFiltering == 0)
-    {
-        std::random_device dev;
-        std::mt19937 rng(dev());
-        std::uniform_int_distribution<std::mt19937::result_type> distribution(1, 4096);
-        mDiscriminatorUseForFiltering = static_cast<uint16_t>(distribution(rng));
-    }
-    return mDiscriminatorUseForFiltering;
-}
-
 void DiscoveryCommands::OnNodeDiscovered(const chip::Dnssd::DiscoveredNodeData & nodeData)
 {
     // TODO: If multiple results are found for the same filter, then the test result depends
     //       on which result comes first. At the moment, the code assume that there is only
     //       a single match on the network, but if that's not enough, there may be a need
     //       to implement some sort of list that is built for a given duration before returning
-    //
-    //       But also, running on CI seems to show cross-talks between CI instances, so multiple
-    //       results will comes up. Unexpected advertisements are filtered by validating the
-    //       discriminator from the advertisement matches the one coming from the config section
-    //       of the test.
-    if (nodeData.longDiscriminator != GetUniqueDiscriminator())
-    {
-        ChipLogError(chipTool, "Non fatal error: Unexpected node advertisment. It will be ignored");
-        nodeData.LogDetail();
-        return;
-    }
-
     ReturnOnFailure(TearDownDiscoveryCommands());
 
     nodeData.LogDetail();

src/app/tests/suites/commands/discovery/DiscoveryCommands.h

@@ -69,12 +69,7 @@ class DiscoveryCommands : public chip::Dnssd::CommissioningResolveDelegate
     /////////// CommissioningDelegate Interface /////////
     void OnNodeDiscovered(const chip::Dnssd::DiscoveredNodeData & nodeData) override;
 
-protected:
-    // This function initialize a random discriminator once and returns it all the time afterwards
-    uint16_t GetUniqueDiscriminator();
-
 private:
     bool mReady = false;
     chip::Dnssd::ResolverProxy mDNSResolver;
-    uint16_t mDiscriminatorUseForFiltering = 0;
 };