Fix lint (assert.ErrorIs) and remove incorrect login profile+arg conflict

The testifylint linter requires assert.ErrorIs over assert.True(errors.Is).

The blanket rejection of positional arg + --profile in login was wrong:
`databricks auth login https://host --profile myprofile` is valid (host as
positional arg with explicit profile). The profile-first resolution already
skips when profileName is set, so no extra guard is needed.

Co-authored-by: Isaac

Author: simonfaltum

cmd/auth/login.go

@@ -150,9 +150,6 @@ a new profile is created.
 		}
 
 		// Resolve positional argument as profile or host.
-		if len(args) > 0 && cmd.Flag("profile").Changed {
-			return errors.New("please only provide a positional argument or --profile, not both")
-		}
 		if len(args) > 0 && authArguments.Host != "" {
 			return errors.New("please only provide a positional argument or --host, not both")
 		}

cmd/auth/resolve_test.go

@@ -1,7 +1,6 @@
 package auth
 
 import (
-	"errors"
 	"testing"
 
 	"github.com/databricks/cli/libs/cmdio"
@@ -89,7 +88,7 @@ func TestResolvePositionalArg(t *testing.T) {
 			profiler := profile.InMemoryProfiler{Profiles: tc.profiles}
 			profileName, host, err := resolvePositionalArg(ctx, tc.arg, profiler)
 			if tc.wantErr != nil {
-				assert.True(t, errors.Is(err, tc.wantErr), "expected %v, got %v", tc.wantErr, err)
+				assert.ErrorIs(t, err, tc.wantErr)
 				return
 			}
 			require.NoError(t, err)