5005 make style of oui label in tables consistent with the normal text style

Replace the existing comment, which seemed redundant, with a description
of what the helper method does.

Refs #5005

The label previously took on the colour of the icon (green or red) and
was set in Times/browser default.

It was set in the wrong style because the label was put inside the
`<span>` for the icon. To fix the problem, leave the icon `<span>` empty
and put the label just after it in a text DOM node. This makes the text
label render correctly, in black 14px Open Sans.

Also remove the unnecessary `cls` variables and ternaries as these are
already handled by the outer `if` condition.

Refs #5005

NetexImport: Don't destroy non-existent Referentials

Luc discovered this error in my method that destroys associated
non-ready `Referential`s:

    > WorkbenchImport.destroy_all
      WorkbenchImport Load (3.0ms)  SELECT "public"."imports".* FROM "public"."imports" WHERE "public"."imports"."type" IN ('WorkbenchImport')
       (1.5ms)  BEGIN
      ImportMessage Load (2.7ms)  SELECT "public"."import_messages".* FROM "public"."import_messages" WHERE "public"."import_messages"."import_id" = $1  [["import_id", 58]]
      ImportResource Load (1.9ms)  SELECT "public"."import_resources".* FROM "public"."import_resources" WHERE "public"."import_resources"."import_id" = $1  [["import_id", 58]]
      Import Load (0.3ms)  SELECT "public"."imports".* FROM "public"."imports" WHERE "public"."imports"."parent_id" = $1  [["parent_id", 58]]
      ImportMessage Load (0.5ms)  SELECT "public"."import_messages".* FROM "public"."import_messages" WHERE "public"."import_messages"."import_id" = $1  [["import_id", 59]]
      ImportResource Load (4.8ms)  SELECT "public"."import_resources".* FROM "public"."import_resources" WHERE "public"."import_resources"."import_id" = $1  [["import_id", 59]]
      SQL (1.3ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 636]]
      SQL (0.3ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 635]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 634]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 633]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 632]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 631]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 630]]
      SQL (0.1ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 629]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 628]]
      SQL (0.1ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 627]]
      SQL (0.1ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 626]]
      SQL (0.3ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 625]]
      SQL (0.3ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 624]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 623]]
      SQL (0.2ms)  DELETE FROM "public"."import_resources" WHERE "public"."import_resources"."id" = $1  [["id", 622]]
      Import Load (0.3ms)  SELECT "public"."imports".* FROM "public"."imports" WHERE "public"."imports"."parent_id" = $1  [["parent_id", 59]]
      Referential Load (0.6ms)  SELECT  "public"."referentials".* FROM "public"."referentials" WHERE "public"."referentials"."id" = $1 LIMIT 1  [["id", 18]]
       (0.2ms)  ROLLBACK
    NoMethodError: undefined method `ready' for nil:NilClass
    from .../stif-boiv/app/models/netex_import.rb:20:in `destroy_non_ready_referential'

Since `referential` is not a required attribute, it can be nil. That was
causing this to break because I tried to destroy a `Referential` that
doesn't exist. Check that there's an associated `Referential` before
trying to destroy it.

Refs #4991

4823 compliance check show

4461 netext import error wo referential