use an env var for configurable proxy header (#8863)

src/state/queries/messages/update-all-read.ts

@@ -1,8 +1,8 @@
-import {ChatBskyConvoListConvos} from '@atproto/api'
+import {type ChatBskyConvoListConvos} from '@atproto/api'
 import {useMutation, useQueryClient} from '@tanstack/react-query'
 
+import {DM_SERVICE_HEADERS} from '#/lib/constants'
 import {logger} from '#/logger'
-import {DM_SERVICE_HEADERS} from '#/state/queries/messages/const'
 import {useAgent} from '#/state/session'
 import {RQKEY as CONVO_LIST_KEY} from './list-conversations'