Fix bug in device path proto reading

aconfig_device_paths uses `include_str!` to include a text file
containing comma-separated strings with each partition aconfig file.
The lib does not handle the escaped newlines and quotation marks.
Adds proper handling.

Test: cargo t  && m -j120 && acloud create --local-image && adb shell aflags list
Bug: 340514768
Change-Id: I75214bf02dd962d8291f1654ade8cbce1cda9fde