Update polkadot deps to support xt v5 and refactor code to handle new private identifiers

[clangenb]

Closes #141

After the update in #142, we got several errors like "Cannot read private field". This is because private fields were introduced in the meantime in JS and Vue or Pinia-stores strip them under certain circumstances.

• Do not store complex objects in the store if possible (e.g. the worker).

• When handling reactive objects declared with ref we do:

  • If we need to pass the object to the UI template, but we don't need reactivity (e.g. shieldingTargetApi), we assign the value like shieldingTargetApi.value = markRaw(api);
  • If we need reactivity, we can not mark it as raw, but we can convert them to a raw object before accessing internal private fields e.g. toRaw(notesBucketInfo). Note: simple things like Option.unwrap() need internal private state.
  • If we don't need reactivity, nor passing them into a UI-template, variables should just be regular variables.

• Other changes:

  • Fixed bunch of warnings during the debugging phase.

Tested:

• Unshield works (DOT production)
• Private transfer works (DOT production)

[brenzi]

LGTM