settings_profile_fields: Clean up field_id type confusion.
settings_profile_fields: Clean up field_id type confusion.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulipchat.com>

shubhamdhama/zulip,synicalsyntax/zulip,andersk/zulip,punchagan/zulip,synicalsyntax/zulip,shubhamdhama/zulip,zulip/zulip,synicalsyntax/zulip,rht/zulip,shubhamdhama/zulip,hackerkid/zulip,synicalsyntax/zulip,synicalsyntax/zulip,showell/zulip,zulip/zulip,eeshangarg/zulip,eeshangarg/zulip,hackerkid/zulip,brainwane/zulip,showell/zulip,shubhamdhama/zulip,showell/zulip,showell/zulip,zulip/zulip,timabbott/zulip,punchagan/zulip,andersk/zulip,andersk/zulip,brainwane/zulip,showell/zulip,kou/zulip,synicalsyntax/zulip,shubhamdhama/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,rht/zulip,andersk/zulip,brainwane/zulip,brainwane/zulip,kou/zulip,showell/zulip,showell/zulip,brainwane/zulip,rht/zulip,punchagan/zulip,kou/zulip,punchagan/zulip,hackerkid/zulip,timabbott/zulip,brainwane/zulip,shubhamdhama/zulip,zulip/zulip,hackerkid/zulip,rht/zulip,kou/zulip,rht/zulip,hackerkid/zulip,synicalsyntax/zulip,timabbott/zulip,eeshangarg/zulip,punchagan/zulip,timabbott/zulip,punchagan/zulip,eeshangarg/zulip,hackerkid/zulip,timabbott/zulip,rht/zulip,andersk/zulip,andersk/zulip,zulip/zulip,timabbott/zulip,hackerkid/zulip,brainwane/zulip,eeshangarg/zulip,andersk/zulip,rht/zulip,shubhamdhama/zulip,zulip/zulip,timabbott/zulip,eeshangarg/zulip,kou/zulip,punchagan/zulip