[fenix] Bug 1815424 - Show Dialog should not be called multiple times.

app/src/main/java/org/mozilla/fenix/browser/BaseBrowserFragment.kt

@@ -520,6 +520,8 @@ abstract class BaseBrowserFragment :
                 requestPermissions(permissions, REQUEST_CODE_DOWNLOAD_PERMISSIONS)
             },
             customFirstPartyDownloadDialog = { filename, contentSize, positiveAction, negativeAction ->
+                run {
+                    if (currentStartDownloadDialog == null) {
                         FirstPartyDownloadDialog(
                             activity = requireActivity(),
                             filename = filename.value,
@@ -528,11 +530,16 @@ abstract class BaseBrowserFragment :
                             negativeButtonAction = negativeAction.value,
                         ).onDismiss {
                             currentStartDownloadDialog = null
-                }.show(binding.startDownloadDialogContainer).also {
+                        }.show(binding.startDownloadDialogContainer)
+                            .also {
                                 currentStartDownloadDialog = it
                             }
+                    }
+                }
             },
             customThirdPartyDownloadDialog = { downloaderApps, onAppSelected, negativeActionCallback ->
+                run {
+                    if (currentStartDownloadDialog == null) {
                         ThirdPartyDownloadDialog(
                             activity = requireActivity(),
                             downloaderApps = downloaderApps.value,
@@ -543,6 +550,8 @@ abstract class BaseBrowserFragment :
                         }.show(binding.startDownloadDialogContainer).also {
                             currentStartDownloadDialog = it
                         }
+                    }
+                }
             },
         )