enhance this logs intelligibility to set global postage batch slider in swarm extension

[tamas6]

for example this occurs when Registering new account, and global postage stamp switch is not on, text could have bee "please check if Global Postage Stamp slider is ON"

[crtahlin]

Please triage, @nugaon.

[nugaon]

Swarm Extension has already postageBatch.isGlobalPostageBatchEnabled() function that gives back whether postage batch is enabled or not. that should be just checked in the UI.