(core) Use MetaTableData more

Summary:
Add more method overrides to MetaTableData for extra type safety.

Use MetaTableData, MetaRowRecord, and getMetaTable in more places.

Test Plan: Mostly it just has to compile. Tested manually that types are being checked more strictly now, e.g. by adding a typo to property names. Some type casting has also been removed.

Reviewers: dsagal

Reviewed By: dsagal

Subscribers: dsagal

Differential Revision: https://phab.getgrist.com/D3168

app/server/lib/DocPluginManager.ts

@@ -33,8 +33,8 @@ class GristDocAPIImpl implements GristDocAPI {
   public async getDocName() { return this._activeDoc.docName; }
 
   public async listTables(): Promise<string[]> {
-    const table = this._activeDoc.docData!.getTable('_grist_Tables')!;
-    return (table.getColValues('tableId') as string[])
+    const table = this._activeDoc.docData!.getMetaTable('_grist_Tables');
+    return table.getColValues('tableId')
       .filter(id => !id.startsWith("GristSummary_")).sort();
   }