This patch-set consolidates and corrects rjson string conversion handling.
It removes unnecessary string copies, ensures proper length usage and
replaces ad-hoc conversions with consistent helper functions.
Overall, the changes make rjson string handling safer, faster, and more uniform across the codebase.
Backport: no, it's a refactor
Closesscylladb/scylladb#27394
* github.com:scylladb/scylladb:
fix rjson::value to bytes conversion with missing GetStringLength call
alternator: change type from string to string_view in should_add_capacity
fix rjson::value to string_view conversion with missing GetStringLength call
use rjson::to_string_view when rjson::value gets converted using GetStringLength
use rjson::to_sstring and rjson::to_string for various string conversions
utils: use rjson document wrapper in instance_profile_credentials_provider::parse_creds
utils: move rjson::to_string_view func to string related place
utils: add to_sstring and to_string rjson helper