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/util/keypair_test.go

@@ -13,6 +13,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestKeygen(t *testing.T) {
@@ -55,6 +56,8 @@ func TestSignUsingKeys(t *testing.T) {
 	assert.NoError(t, err)
 
 	// Verify
-	err = rsa.VerifyPKCS1v15(pubParsed.(*rsa.PublicKey), crypto.SHA256, d, sig)
+	pubKey, ok := pubParsed.(*rsa.PublicKey)
+	require.True(t, ok)
+	err = rsa.VerifyPKCS1v15(pubKey, crypto.SHA256, d, sig)
 	assert.NoError(t, err)
 }