Remove orphaned TestFormatDependencyType test

The formatDependencyType function was intentionally removed in commit
57b6ea6 when the dependency display UI was simplified. The test was
left behind and is now failing CI.

Amp-Thread-ID: https://ampcode.com/threads/T-24a71c8b-3e1f-4e9f-91dd-3053096e3d7e
Co-authored-by: Amp <amp@ampcode.com>

cmd/bd/show_test.go

@@ -1,30 +1,3 @@
 package main
 
-import (
-	"testing"
 
-	"github.com/steveyegge/beads/internal/types"
-)
-
-func TestFormatDependencyType(t *testing.T) {
-	tests := []struct {
-		name     string
-		depType  types.DependencyType
-		expected string
-	}{
-		{"blocks", types.DepBlocks, "blocks"},
-		{"related", types.DepRelated, "related"},
-		{"parent-child", types.DepParentChild, "parent-child"},
-		{"discovered-from", types.DepDiscoveredFrom, "discovered-from"},
-		{"unknown", types.DependencyType("unknown"), "unknown"},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := formatDependencyType(tt.depType)
-			if result != tt.expected {
-				t.Errorf("formatDependencyType(%v) = %v, want %v", tt.depType, result, tt.expected)
-			}
-		})
-	}
-}