There was a discrepancy between TemplateTag id types as defined in metabase.lib.native (uuid) and metabase.mbql.schema (string). This PR makes string the uniform type for both. This results in errors when code using different specs for the same logical entity is used together. Here's an breaking example:

```
(let [card-id 328 ;; This is a valid card locally
      q   (str "SELECT * FROM {{#" card-id "}} LIMIT 2")
      tt  (lib-native/extract-template-tags q)
      res (qp/process-query
            {:database 1
             :type     :native
             :native   {:query         q
                        :template-tags tt}})]
  (is (some? res)))
```
This will break since the tt generated id is a uuid but process-query expects a string id.

Fixes #31252