[processing] List 'All files (*.*)' option last in save as dialogs

See https://ux.stackexchange.com/questions/111689/file-dialog-formats-list-should-all-files-be-listed-first-or-last for discussion:

- for 'file open' dialogs, wildcard options should be listed first
- for 'file save' dialogs, wildcard options should be listed last

python/plugins/processing/gui/ParameterGuiUtils.py

@@ -62,7 +62,7 @@ def getFileFilter(param):
         exts = dataobjects.getSupportedOutputRasterLayerExtensions()
         for i in range(len(exts)):
             exts[i] = tr('{0} files (*.{1})', 'QgsProcessingParameterRasterDestination').format(exts[i].upper(), exts[i].lower())
-        return tr('All files (*.*)') + ';;' + ';;'.join(exts)
+        return ';;'.join(exts) + ';;' + tr('All files (*.*)')
     elif param.type() == 'table':
         exts = ['csv', 'dbf']
         for i in range(len(exts)):
@@ -72,12 +72,12 @@ def getFileFilter(param):
         exts = QgsVectorFileWriter.supportedFormatExtensions()
         for i in range(len(exts)):
             exts[i] = tr('{0} files (*.{1})', 'ParameterVector').format(exts[i].upper(), exts[i].lower())
-        return tr('All files (*.*)') + ';;' + ';;'.join(exts)
+        return ';;'.join(exts) + ';;' + tr('All files (*.*)')
     elif param.type() == 'source':
         return QgsProviderRegistry.instance().fileVectorFilters()
     elif param.type() == 'vector':
         return QgsProviderRegistry.instance().fileVectorFilters()
     elif param.type() == 'fileDestination':
-        return tr('All files (*.*)') + ';;' + param.fileFilter()
+        return param.fileFilter() + ';;' + tr('All files (*.*)')
 
     return ''