Fix dashboard filter width in edit mode (#36483)

* Use `minWidth` instead of `width`

* Reserve left padding for the settings icon

frontend/src/metabase/parameters/components/ParameterWidget/ParameterWidget.jsx

 /* eslint-disable react/prop-types */
 import { Component } from "react";
 import PropTypes from "prop-types";
-import { Icon } from "metabase/core/components/Icon";
 import ParameterValueWidget from "../ParameterValueWidget";
 import {
   ParameterContainer,
   ParameterFieldSet,
+  SettingsIcon,
 } from "./ParameterWidget.styled";
 
 export class ParameterWidget extends Component {
@@ -109,7 +109,7 @@ export class ParameterWidget extends Component {
           {dragHandle}
         </div>
         {parameter.name}
-        <Icon className="flex-align-right" name="gear" size={16} />
+        <SettingsIcon name="gear" size={16} />
       </ParameterContainer>
     );
 

frontend/src/metabase/parameters/components/ParameterWidget/ParameterWidget.styled.ts

 import styled from "@emotion/styled";
 import FieldSet from "metabase/components/FieldSet";
+import { Icon } from "metabase/core/components/Icon";
 import { color } from "metabase/lib/colors";
 
 interface ParameterFieldSetProps {
@@ -43,7 +44,7 @@ export const ParameterContainer = styled.div<ParameterContainerProps>`
   border-radius: 0.5rem;
   cursor: pointer;
   font-weight: bold;
-  width: 170px;
+  min-width: 170px;
   margin-right: 0.5rem;
   margin-bottom: 0.5rem;
   padding: 0.5rem;
@@ -51,3 +52,8 @@ export const ParameterContainer = styled.div<ParameterContainerProps>`
   background-color: ${props =>
     props.isEditingParameter ? color("brand") : color("white")};
 `;
+
+export const SettingsIcon = styled(Icon)`
+  margin-left: auto;
+  padding-left: 1rem;
+`;