chore: remove unnecessary loop variable captures (#22180)

Since Go 1.22, the loop variable capture issue is resolved. Variables
declared by for loops are now per-iteration rather than per-loop, making
the 'v := v' pattern unnecessary.

coderd/prebuilds/parameters_test.go

@@ -128,7 +128,6 @@ func TestFindMatchingPresetID(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 

coderd/prebuilds/preset_snapshot_test.go

@@ -1193,7 +1193,6 @@ func TestMatchesCron(t *testing.T) {
 	}
 
 	for _, testCase := range testCases {
-		testCase := testCase
 		t.Run(testCase.name, func(t *testing.T) {
 			t.Parallel()
 
@@ -1518,7 +1517,6 @@ func TestCalculateDesiredInstances(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			desiredInstances := tc.snapshot.CalculateDesiredInstances(tc.at)