pause react-queries when not connected

[SvenDowideit]

for react-query v3 - https://react-query-v3.tanstack.com/guides/disabling-queries

but v4 is soon, and has https://tanstack.com/query/v4/docs/examples/react/offline which will be superior.

IMO this can wait til 0.5.0, as its not a regression - but ... if you're not connected, you will (currently) see:

Failed to load resource: net::ERR_CONNECTION_REFUSED
127.0.0.1:8899/:1          Failed to load resource: net::ERR_CONNECTION_REFUSED
query.js:356 TypeError: Failed to fetch
    at ClientBrowser.callServer (connection.ts:1115:23)
    at ClientBrowser.request (index.js:102:8)
    at connection.ts:1154:14
    at new Promise (<anonymous>)
    at Connection._rpcRequest (connection.ts:1153:12)
    at Connection.getParsedTokenAccountsByOwner (connection.ts:2725:34)
    at getTokenAccounts (getAccount.ts:155:39)
    at Object.queryTokenAccounts [as queryFn] (getAccount.ts:170:31)
    at Object.fetchFn2 [as fn] (query.js:298:29)
    at run2 (retryer.js:95:31)
onError @ query.js:356
reject2 @ retryer.js:67
(anonymous) @ retryer.js:132
127.0.0.1:8899/:1          Failed to load resource: net::ERR_CONNECTION_REFUSED
query.js:356 TypeError: Failed to fetch
    at ClientBrowser.callServer (connection.ts:1115:23)
    at ClientBrowser.request (index.js:102:8)
    at connection.ts:1154:14
    at new Promise (<anonymous>)
    at Connection._rpcRequest (connection.ts:1153:12)
    at Connection.getParsedAccountInfo (connection.ts:2818:34)
    at getParsedAccount (getAccount.ts:47:36)
    at Object.queryParsedAccount [as queryFn] (getAccount.ts:76:29)
    at Object.fetchFn2 [as fn] (query.js:298:29)
    at run2 (retryer.js:95:31)
onError @ query.js:356
reject2 @ retryer.js:67
(anonymous) @ retryer.js:132
connection.ts:1115          POST http://127.0.0.1:8899/ net::ERR_CONNECTION_REFUSED
(anonymous) @ connection.ts:1115
ClientBrowser.request @ index.js:102
(anonymous) @ connection.ts:1154
(anonymous) @ connection.ts:1153
getEpochInfo @ connection.ts:3345
validatorState @ ValidatorNetwork.tsx:22
(anonymous) @ ValidatorNetwork.tsx:35
commitHookEffectListMount @ react-dom.development.js:23150
commitPassiveMountOnFiber @ react-dom.development.js:24926
commitPassiveMountEffects_complete @ react-dom.development.js:24891
commitPassiveMountEffects_begin @ react-dom.development.js:24878
commitPassiveMountEffects @ react-dom.development.js:24866
flushPassiveEffectsImpl @ react-dom.development.js:27039
flushPassiveEffects @ react-dom.development.js:26984
commitRootImpl @ react-dom.development.js:26935
commitRoot @ react-dom.development.js:26682
performSyncWorkOnRoot @ react-dom.development.js:26117
flushSyncCallbacks @ react-dom.development.js:12042
(anonymous) @ react-dom.development.js:25651
connection.ts:1115          POST http://127.0.0.1:8899/ net::ERR_CONNECTION_REFUSED