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/binding_test.go

@@ -51,8 +51,6 @@ type FooBarFileStruct struct {
 type FooBarFileFailStruct struct {
 	FooBarStruct
 	File *multipart.FileHeader `invalid_name:"file" binding:"required"`
-	// for unexport test
-	data *multipart.FileHeader `form:"data" binding:"required"`
 }
 
 type FooDefaultBarStruct struct {
@@ -1063,7 +1061,7 @@ func testFormBindingInvalidName(t *testing.T, method, path, badPath, body, badBo
 	}
 	err := b.Bind(req, &obj)
 	require.NoError(t, err)
-	assert.Equal(t, "", obj.TestName)
+	assert.Empty(t, obj.TestName)
 
 	obj = InvalidNameType{}
 	req = requestWithBody(method, badPath, badBody)
@@ -1318,7 +1316,7 @@ func testBodyBindingFail(t *testing.T, b Binding, name, path, badPath, body, bad
 	req := requestWithBody(http.MethodPost, path, body)
 	err := b.Bind(req, &obj)
 	require.Error(t, err)
-	assert.Equal(t, "", obj.Foo)
+	assert.Empty(t, obj.Foo)
 
 	obj = FooStruct{}
 	req = requestWithBody(http.MethodPost, badPath, badBody)