Revert "fix: geojson invalid query on unavailable PostGIS"

This reverts commit 0f1ca8faac.

Reverting for now as it adds one more query to the schema cache and
there's no clear way forward on how to integrate the fix with the
current schema cache queries.

See discussion on
https://github.com/PostgREST/postgrest/pull/4246#pullrequestreview-3093174224.

src/PostgREST/SchemaCache.hs

@@ -152,7 +152,6 @@ querySchemaCache conf@AppConfig{..} = do
   reps    <- SQL.statement conf $ dataRepresentations prepared
   mHdlers <- SQL.statement conf $ mediaHandlers prepared
   tzones  <- SQL.statement mempty $ timezones prepared
-  hasPgis <- SQL.statement conf $ postgisFunc prepared
   _       <-
     let sleepCall = SQL.Statement "select pg_sleep($1 / 1000.0)" (param HE.int4) HD.noResult prepared in
     whenJust configInternalSCSleep (`SQL.statement` sleepCall) -- only used for testing
@@ -165,7 +164,7 @@ querySchemaCache conf@AppConfig{..} = do
     , dbRelationships = getOverrideRelationshipsMap rels cRels
     , dbRoutines = funcs
     , dbRepresentations = reps
-    , dbMediaHandlers = HM.union mHdlers $ initialMediaHandlers hasPgis -- the custom handlers will override the initial ones
+    , dbMediaHandlers = HM.union mHdlers initialMediaHandlers -- the custom handlers will override the initial ones
     , dbTimezones = tzones
     }
   where
@@ -1049,14 +1048,12 @@ allViewsKeyDependencies =
       having ncol = array_length(array_agg(row(col.attname, view_columns) order by pks_fks.ord), 1)
       |]
 
-initialMediaHandlers :: Bool -> MediaHandlerMap
-initialMediaHandlers hasPostgisFunc =
+initialMediaHandlers :: MediaHandlerMap
+initialMediaHandlers =
   HM.insert (RelAnyElement, MediaType.MTAny            ) (BuiltinOvAggJson,    MediaType.MTApplicationJSON) $
   HM.insert (RelAnyElement, MediaType.MTApplicationJSON) (BuiltinOvAggJson,    MediaType.MTApplicationJSON) $
   HM.insert (RelAnyElement, MediaType.MTTextCSV        ) (BuiltinOvAggCsv,     MediaType.MTTextCSV) $
-  (if hasPostgisFunc
-    then HM.insert (RelAnyElement, MediaType.MTGeoJSON        ) (BuiltinOvAggGeoJson, MediaType.MTGeoJSON)
-    else mempty)
+  HM.insert (RelAnyElement, MediaType.MTGeoJSON        ) (BuiltinOvAggGeoJson, MediaType.MTGeoJSON)
   HM.empty
 
 mediaHandlers :: Bool -> SQL.Statement AppConfig MediaHandlerMap
@@ -1142,35 +1139,6 @@ timezones = SQL.Statement sql HE.noParams decodeTimezones
     decodeTimezones :: HD.Result TimezoneNames
     decodeTimezones = S.fromList <$> HD.rowList (column HD.text)
 
-
--- Find the postgis function that has the signature:
--- st_asgeojson(record,...) returns text
-postgisFunc :: Bool -> SQL.Statement AppConfig Bool
-postgisFunc = SQL.Statement sql params decoder
-  where
-    params =
-      (map escapeIdent . toList . configDbSchemas >$< arrayParam HE.text) <>
-      (map escapeIdent . toList . configDbExtraSearchPath >$< arrayParam HE.text)
-    decoder = HD.singleRow (column HD.bool)
-    sql = encodeUtf8 [trimming|
-    SELECT
-      exists(
-        SELECT
-          1
-        FROM pg_catalog.pg_proc      AS p
-        JOIN pg_catalog.pg_depend    AS d
-          ON  d.objid   = p.oid
-          AND d.deptype = 'e'
-        JOIN pg_catalog.pg_extension AS e
-          ON e.oid   = d.refobjid
-        WHERE p.pronamespace   = ANY($$1::regnamespace[] || $$2::regnamespace[])
-          AND p.proname        = 'st_asgeojson'
-          AND e.extname        = 'postgis'
-          AND p.proargtypes[0] = 'record'::regtype
-          AND pg_get_function_result(p.oid) = 'text'
-      );
-    |]
-
 param :: HE.Value a -> HE.Params a
 param = HE.param . HE.nonNullable