Fix leaks of keys in Matter.framework unit tests.

We need to CFRelease the return from SecKeyCreateWithData, and we were not doing that.

Author: bzbarsky-apple

src/darwin/Framework/CHIPTests/MTRCertificateValidityTests.m

@@ -163,6 +163,8 @@ - (void)issueOperationalCertificateForRequest:(MTROperationalCSRInfo *)csrInfo
 
     __auto_type * operationalCertificate = [self issueOperationalCertificateForNode:@(kDeviceId)
                                                                operationalPublicKey:operationalPublicKey];
+    // Release no-longer-needed key key before we do anything else.
+    CFRelease(operationalPublicKey);
     XCTAssertNotNil(operationalCertificate);
 
     __auto_type * certChain = [[MTROperationalCertificateChain alloc] initWithOperationalCertificate:operationalCertificate

src/darwin/Framework/CHIPTests/MTRPerControllerStorageTests.m

@@ -158,6 +158,8 @@ - (void)issueOperationalCertificateForRequest:(MTROperationalCSRInfo *)csrInfo
                                                                            nodeID:self.nextNodeID
                                                             caseAuthenticatedTags:nil
                                                                             error:&error];
+    // Release no-longer-needed key key before we do anything else.
+    CFRelease(publicKey);
     XCTAssertNil(error);
     XCTAssertNotNil(operationalCert);