ensure package callbacks are invoked when no valid precompile file exists for an "auto loaded" stdlib (#54248)

The `_require` call skips the logic for running package callbacks (and
extension triggers) so if Pkg is loaded in the startup file and then
REPL failed to load from `_require_search_from_serialized` (and instead
loaded via `_require`) the REPL extension from Pkg would not load.

Author: KristofferC

base/loading.jl

@@ -2547,7 +2547,7 @@ function require_stdlib(uuidkey::PkgId, ext::Union{Nothing, String}=nothing)
         run_package_callbacks(uuidkey)
     else
         # if the user deleted their bundled depot, next try to load it completely normally
-        newm = _require(uuidkey)
+        newm = _require_prelocked(uuidkey)
     end
     return newm
     end