Fixed: Don't convert artist/album selection filter to lower case in state

(cherry picked from commit ca52eb76ca2e286479f1803f399d5f5b563cfb41)

Closes #1857

frontend/src/InteractiveImport/Album/SelectAlbumModalContent.js

@@ -55,7 +55,7 @@ class SelectAlbumModalContent extends Component {
   // Listeners
 
   onFilterChange = ({ value }) => {
-    this.setState({ filter: value.toLowerCase() });
+    this.setState({ filter: value });
   };
 
   //
@@ -71,6 +71,7 @@ class SelectAlbumModalContent extends Component {
     } = this.props;
 
     const filter = this.state.filter;
+    const filterLower = filter.toLowerCase();
 
     return (
       <ModalContent onModalClose={onModalClose}>
@@ -107,7 +108,7 @@ class SelectAlbumModalContent extends Component {
                 <TableBody>
                   {
                     items.map((item) => {
-                      return item.title.toLowerCase().includes(filter) ?
+                      return item.title.toLowerCase().includes(filterLower) ?
                         (
                           <SelectAlbumRow
                             key={item.id}

frontend/src/InteractiveImport/Artist/SelectArtistModalContent.js

@@ -29,7 +29,7 @@ class SelectArtistModalContent extends Component {
   // Listeners
 
   onFilterChange = ({ value }) => {
-    this.setState({ filter: value.toLowerCase() });
+    this.setState({ filter: value });
   };
 
   //
@@ -43,6 +43,7 @@ class SelectArtistModalContent extends Component {
     } = this.props;
 
     const filter = this.state.filter;
+    const filterLower = filter.toLowerCase();
 
     return (
       <ModalContent onModalClose={onModalClose}>
@@ -69,7 +70,7 @@ class SelectArtistModalContent extends Component {
           >
             {
               items.map((item) => {
-                return item.artistName.toLowerCase().includes(filter) ?
+                return item.artistName.toLowerCase().includes(filterLower) ?
                   (
                     <SelectArtistRow
                       key={item.id}