Fix #4843: Redundant hash in ghcide cache path

Reasoning:
The upstream logic might send unit ID that already has a hash appended to it to prevent collision.
Later in the pipeline , the getCacheDirsDefault function blindly appends the  opts hash again to generate the cache path. This results in a duplicated hash (main-<hash>-<hash>).
This patch does a simple isSuffixOf check to ensure the hash is only appended by the getCacheDirsDefalut if wansn't already appened upstream, keeping the cache directory clean.

Author: adpad-13

ghcide/session-loader/Development/IDE/Session.hs

@@ -1220,7 +1220,11 @@ setODir f d =
 
 getCacheDirsDefault :: String -> [String] -> IO CacheDirs
 getCacheDirsDefault prefix opts = do
-    dir <- Just <$> getXdgDirectory XdgCache (cacheDir </> prefix ++ "-" ++ opts_hash)
+    let suffix = "-"++opts_hash
+        dirName = if suffix `isSuffixOf` prefix
+                    then prefix
+                    else prefix ++ suffix
+    dir <- Just <$> getXdgDirectory XdgCache (cacheDir </> dirName)
     return $ CacheDirs dir dir dir
     where
         -- Create a unique folder per set of different GHC options, assuming that each different set of