Update headwords when Entry.MorphType or MorphType tokens change

[myieye]

Now that FTS rows have calculated headwords based on morph-types, we need additional EF interceptors that update the headwords when necessary.

We already have an interceptor that updates the FTS row when the respective entry is updated. Now we just need to extend that to morph-types:

• When an entry's morph-type changes, its headword needs to be recalculated
• When a morph-type's configured tokens change, the headwords of all entries of that morph-type need to be recalculated

CodeRabbit also happened to pick up on this and may or may not have useful suggestions: #2202 (comment)