L10n fix for IW locale in storage_summary string

storage_summary is passed as a single string of format "32 GB".
Spliting the phrase to allow TC to remove whitespace in case of iw
translations.

Old Translation : <free_space>
New Translation: <free_space_value> <free_space_unit>

Bug: 387197875
Test: manual
Flag: EXEMPT bugfix
Change-Id: I91abf58df472650a6278b08e4daa5d32e7f90da9