fix poster width (#138)

ErsatzTV/Pages/Movie.razor

@@ -19,7 +19,7 @@
         @if (!string.IsNullOrWhiteSpace(_movie.Poster))
         {
             <img class="mud-elevation-2 mr-6"
-                 style="border-radius: 4px; max-height: 440px"
+                 style="border-radius: 4px; max-height: 440px; flex-shrink: 0"
                  src="@($"/artwork/posters/{_movie.Poster}")" alt="movie poster"/>
         }
         <div style="display: flex; flex-direction: column; height: 100%">

ErsatzTV/Pages/TelevisionEpisodeList.razor

@@ -29,7 +29,7 @@
         @if (!string.IsNullOrWhiteSpace(_season.Poster))
         {
             <img class="mud-elevation-2 mr-6"
-                 style="border-radius: 4px; max-height: 440px"
+                 style="border-radius: 4px; max-height: 440px; flex-shrink: 0"
                  src="@($"/artwork/posters/{_season.Poster}")" alt="show poster"/>
         }
         <div style="display: flex; flex-direction: column; height: 100%">

ErsatzTV/Pages/TelevisionSeasonList.razor

@@ -27,7 +27,7 @@
         @if (!string.IsNullOrWhiteSpace(_show.Poster))
         {
             <img class="mud-elevation-2 mr-6"
-                 style="border-radius: 4px; max-height: 440px"
+                 style="border-radius: 4px; max-height: 440px; flex-shrink: 0"
                  src="@($"/artwork/posters/{_show.Poster}")" alt="show poster"/>
         }
         <div style="display: flex; flex-direction: column; height: 100%">