update nightly to ghc-9.8.4

closes #7578
closes #7589

build-constraints.yaml

@@ -1,7 +1,7 @@
 ghc-major-version: "9.8"
 
 # new curator is supposed to use exact GHC version
-ghc-version: "9.8.3"
+ghc-version: "9.8.4"
 
 # This affects which version of the Cabal file format we allow. We
 # should ensure that this is always no greater than the version
@@ -5208,7 +5208,7 @@ packages:
         - ansi-terminal
         - ansi-terminal-types
         - companion
-        - stack < 0 # https://github.com/commercialhaskell/stackage/issues/7578
+        - stack < 9
         - static-bytes
         - pantry
 
@@ -8048,10 +8048,6 @@ packages:
         # https://github.com/commercialhaskell/stackage/issues/7587
         - linux-namespaces < 0.2
 
-        # https://github.com/commercialhaskell/stackage/issues/7589
-        - ghc-lib < 9.8.4
-        - ghc-lib-parser < 9.8.4
-
         # https://github.com/commercialhaskell/stackage/issues/7594
         - tagged < 0.8.9