fix: the address screen shows a token just added at its fetched balance, not 0.0000 (closes #516)

A balance refresh that returns now draws the balances on AddressDetail or
AddressToken again when that screen is up, not only the wallet list. Their
transaction lists are left alone.

Every add path on AddToken and SettingsAddToken tracks a token through
trackToken(), which gives the tracked record `balanceNotFetched: true`. While
the field is set, the token's line reads `quantity unknown` instead of 0.0000.
The popup's refresh deletes the field once it has read the token's balance at
every address. refreshBalances() now resolves with those tokens. The field is
part of the tracked record, so removing the token removes it, and each network
keeps its own records.

Model: opus-5-5

tests/balanceRefreshNetworkSwitch.test.js

@@ -41,6 +41,7 @@ async function holdRefresh(page) {
                 holders: null,
             },
         ];
+        return [];
     });
     const ticking = page.tick();
     await page.settle();