chore: enable forcetypeassert linter, fix issues (#38804)

Enable [`forcetypeassert`](https://github.com/gostaticanalysis/forcetypeassert)
linter to prevent unchecked type assertions. ~650 issues fixed, most
fixes were clean, some use `setting.PanicInDevOrTesting`.

The only behaviour changes are where code would previously send a 500 error
or panic, a 4xx error is now emitted.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/cache/context_test.go

@@ -25,7 +25,7 @@ func TestWithCacheContext(t *testing.T) {
 	c.Put(field, "my_config1", 1)
 	v, _ = c.Get(field, "my_config1")
 	assert.NotNil(t, v)
-	assert.Equal(t, 1, v.(int))
+	assert.Equal(t, 1, v)
 
 	c.Delete(field, "my_config1")
 	c.Delete(field, "my_config2") // remove a non-exist key