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>

routers/common/middleware.go

@@ -95,7 +95,7 @@ func RequestContextHandler() func(h http.Handler) http.Handler {
 				// The "req" might have changed due to the new "req.WithContext" calls
 				// For example: in NewBaseContext, a new "req" with context is created, and the multipart-form is parsed there.
 				// So we always use the latest "req" from the data store.
-				ctxReq := ds.GetContextValue(httplib.RequestContextKey).(*http.Request)
+				ctxReq := ds.GetContextValue(httplib.RequestContextKey).(*http.Request) //nolint:forcetypeassert // must be valid
 				if ctxReq.MultipartForm != nil {
 					_ = ctxReq.MultipartForm.RemoveAll() // remove the temp files buffered to tmp directory
 				}