fix: consider empty wallet as no wallet in asset search

[gomesalexandre]

Description

As mentioned in the inline comment, since we're not returning out zero'd out balances on assets we don't know of (i.e we don't know what we don't know until the user actually has a balance),
considers the "fresh wallet without a balance" situation the same as having no wallet connected.

Issue (if applicable)

closes #9299

Risk

High Risk PRs Require 2 approvals

What protocols, transaction types, wallets or contract interactions might be affected by this PR?

Low, effectively the exact same logic as no wallet connected

Testing

• No wallet connected and a fresh wallet with 0 balances should return the same results in asset search e.g receive modal
• RUNE should be displayed in asset search e.g receive modal

Engineering

• ^

Operations

• 🏁 My feature is behind a flag and doesn't require operations testing (yet)

• ^

Screenshots (if applicable)

https://jam.dev/c/eda92630-02d0-4ba8-8b55-308634f7ffa0

[0xApotheosis]

Does as promised!

develop vs this branch: