ci(golangci-lint): update configuration and fix lint issues (#4247)

* ci: update golangci-lint configuration and lint settings

- Update golangci-lint to version 2
- Enable new linters and adjust existing ones
- Update lint settings across multiple test files
- Remove unused struct and variable checks
- Add new lint exclusions for generated code and specific directories

Signed-off-by: Flc <four_leaf_clover@foxmail.com>

* ci(github): update golangci-lint-action to v8 and lint version to v2.3.4

Signed-off-by: Flc <four_leaf_clover@foxmail.com>

* ci: downgrade golangci-lint to v2.1.6

Signed-off-by: Flc <four_leaf_clover@foxmail.com>

* ci(golangci): add gofumpt linter and fix related issues- Added gofumpt linter to .golangci.yml

Signed-off-by: Flc <four_leaf_clover@foxmail.com>

* test: ignore testifylint and gofumpt lints in specific test cases

Signed-off-by: Flc <four_leaf_clover@foxmail.com>

* build(deps): remove golang.org/x/lint

- Remove golang.org/x/lint package from go.mod
- Update related dependencies in go.sum

Signed-off-by: flc1125 <four_leaf_clover@foxmail.com>

* build(deps): downgrade golang.org/x/mod and golang.org/x/tools

- Downgrade golang.org/x/mod from v0.24.0 to v0.18.0
- Downgrade golang.org/x/tools from v0.33.0 to v.22.0

These changes are made to address compatibility issues with the current project setup.

Signed-off-by: flc1125 <four_leaf_clover@foxmail.com>

---------

Signed-off-by: Flc <four_leaf_clover@foxmail.com>
Signed-off-by: flc1125 <four_leaf_clover@foxmail.com>

binding/default_validator_test.go

@@ -18,14 +18,16 @@ func TestSliceValidationError(t *testing.T) {
 		{"has nil elements", SliceValidationError{errors.New("test error"), nil}, "[0]: test error"},
 		{"has zero elements", SliceValidationError{}, ""},
 		{"has one element", SliceValidationError{errors.New("test one error")}, "[0]: test one error"},
-		{"has two elements",
+		{
+			"has two elements",
 			SliceValidationError{
 				errors.New("first error"),
 				errors.New("second error"),
 			},
 			"[0]: first error\n[1]: second error",
 		},
-		{"has many elements",
+		{
+			"has many elements",
 			SliceValidationError{
 				errors.New("first error"),
 				errors.New("second error"),