fix: Fix panic for pointer reference

[johansja]

Fixing panic issue when configuration doesn't have the mTLS setup.

dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 2025/10/22 21:29:07 http: panic serving 127.0.0.1:34388: runtime error: invalid memory address or nil pointer dereference
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard goroutine 1244 [running]:
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard net/http.(*conn).serve.func1()
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/net/http/server.go:1873 +0xb9
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard panic({0x1cb43a0?, 0x33b47d0?})
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/runtime/panic.go:920 +0x270
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard github.com/dapr/dashboard/pkg/configurations.(*configurations).getKubernetesConfigurations(0x22ef8e0?, {0x0, 0x0})
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/home/runner/work/dashboard/dashboard/pkg/configurations/configurations.go:115 +0x356
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard github.com/dapr/dashboard/pkg/configurations.(*configurations).GetConfigurations(0x1c8dce0?, {0x0?, 0x1fece54?})
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/home/runner/work/dashboard/dashboard/pkg/configurations/configurations.go:94 +0x22
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard github.com/dapr/dashboard/cmd.getConfigurationsHandler({0x2305d28, 0xc0001780e0}, 0xc0005ec8d0?)
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/home/runner/work/dashboard/dashboard/cmd/webserver.go:313 +0x7a
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard net/http.HandlerFunc.ServeHTTP(0xc000584200?, {0x2305d28?, 0xc0001780e0?}, 0x7fca622f42b8?)
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/net/http/server.go:2141 +0x29
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard github.com/gorilla/mux.(*Router).ServeHTTP(0xc000176480, {0x2305d28, 0xc0001780e0}, 0xc000584100)
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/home/runner/go/pkg/mod/github.com/gorilla/mux@v1.8.1/mux.go:212 +0x1c5
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard net/http.serverHandler.ServeHTTP({0xc0005ec780?}, {0x2305d28?, 0xc0001780e0?}, 0x6?)
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/net/http/server.go:2943 +0x8e
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard net/http.(*conn).serve(0xc00053c000, {0x2313ce0, 0xc000541d40})
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/net/http/server.go:2014 +0x5f4
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard created by net/http.(*Server).Serve in goroutine 1
dapr-dashboard-6d7744b449-ngmvh dapr-dashboard 	/opt/hostedtoolcache/go/1.21.13/x64/src/net/http/server.go:3091 +0x5cb