Plugins: Fix Azure token provider cache panic and auth param nil value (#34252)

* More tests for token cache

* Safeguarding from panic and concurrency fixes

* Update Azure dependencies

* Fix interpolation of empty plugin data

go.mod

@@ -14,7 +14,7 @@ replace k8s.io/client-go => k8s.io/client-go v0.18.8
 require (
 	cloud.google.com/go/storage v1.14.0
 	cuelang.org/go v0.3.2
-	github.com/Azure/azure-sdk-for-go/sdk/azcore v0.14.0
+	github.com/Azure/azure-sdk-for-go/sdk/azcore v0.16.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/azidentity v0.8.0
 	github.com/BurntSushi/toml v0.3.1
 	github.com/Masterminds/semver v1.5.0
@@ -70,6 +70,7 @@ require (
 	github.com/mattn/go-sqlite3 v1.14.7
 	github.com/opentracing/opentracing-go v1.2.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
+	github.com/pkg/browser v0.0.0-20210115035449-ce105d075bb4 // indirect
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/alertmanager v0.21.1-0.20210511232218-7301451eb94d
 	github.com/prometheus/client_golang v1.10.0
@@ -91,11 +92,12 @@ require (
 	github.com/xorcare/pointer v1.1.0
 	github.com/yudai/gojsondiff v1.0.0
 	go.opentelemetry.io/collector v0.25.0
-	golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83
+	golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a
 	golang.org/x/exp v0.0.0-20210220032938-85be41e4509f // indirect
-	golang.org/x/net v0.0.0-20210421230115-4e50805a0758
+	golang.org/x/net v0.0.0-20210510120150-4163338589ed
 	golang.org/x/oauth2 v0.0.0-20210413134643-5e61552d6c78
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
+	golang.org/x/sys v0.0.0-20210514084401-e8d321eab015 // indirect
 	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba
 	golang.org/x/tools v0.1.0
 	gonum.org/v1/gonum v0.9.1