fix(projections): added check to make sure there cannot be 2 projections for the same table (#10439)

# Which Problems Are Solved

It should not be possible to start 2 projections with the same name.

If this happens, it can cause issues with the event store such as events
being skipped/unprocessed and can be very hard/time-consuming to
diagnose.

# How the Problems Are Solved

A check was added to make sure no 2 projections have the same table

Closes https://github.com/zitadel/zitadel/issues/10453

---------

Co-authored-by: Silvan <27845747+adlerhurst@users.noreply.github.com>
(cherry picked from commit 10bd747105)

internal/query/projection/projection_test.go

@@ -0,0 +1,69 @@
+package projection
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/brianvoe/gofakeit/v6"
+	"github.com/stretchr/testify/require"
+	gomock "go.uber.org/mock/gomock"
+)
+
+func TestStart(t *testing.T) {
+	duplicateName := gofakeit.Name()
+	tests := []struct {
+		name        string
+		projections func(t *testing.T) []projection
+		err         error
+	}{
+		{
+			name: "happy path",
+			projections: func(t *testing.T) []projection {
+				ctrl := gomock.NewController(t)
+				projections := make([]projection, 5)
+
+				for i := range 5 {
+					mock := NewMockprojection(ctrl)
+					mock.EXPECT().Start(gomock.Any())
+					mock.EXPECT().String().Return(gofakeit.Name())
+					projections[i] = mock
+				}
+
+				return projections
+			},
+		},
+		{
+			name: "same projection used twice error",
+			projections: func(t *testing.T) []projection {
+				projections := make([]projection, 5)
+
+				ctrl := gomock.NewController(t)
+				mock := NewMockprojection(ctrl)
+				mock.EXPECT().String().Return(duplicateName)
+				mock.EXPECT().Start(gomock.Any())
+				projections[0] = mock
+
+				for i := 1; i < 4; i++ {
+					mock := NewMockprojection(ctrl)
+					mock.EXPECT().String().Return(gofakeit.Name())
+					mock.EXPECT().Start(gomock.Any())
+					projections[i] = mock
+				}
+
+				mock = NewMockprojection(ctrl)
+				mock.EXPECT().String().Return(duplicateName)
+				projections[4] = mock
+
+				return projections
+			},
+			err: fmt.Errorf("projeciton for %s already added", duplicateName),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			projections = tt.projections(t)
+			err := Start(t.Context())
+			require.Equal(t, tt.err, err)
+		})
+	}
+}