refactor(fs)!: remove read_text_file and write_text_file commands (#3605)

`readTextFile` and `writeTextFile` now go through `read_file` and
`write_file`, so the `allow-read-text-file`, `deny-read-text-file`,
`allow-write-text-file` and `deny-write-text-file` permissions are gone;
grant `fs:allow-read-file` and `fs:allow-write-file` instead.

examples/api/src-tauri/capabilities/base.json

@@ -65,7 +65,7 @@
     "fs:allow-rename",
     "fs:allow-mkdir",
     "fs:allow-remove",
-    "fs:allow-write-text-file",
+    "fs:allow-write-file",
     "fs:scope-download-recursive",
     "fs:scope-resource-recursive",
     {