templates: Remove pull-left class and its bootstrap CSS.

The "pull-left" class was used for hidden file type input
in compose_control_buttons.hbs and in the copy code button
in codeblocks. It was only used to set the float property
in CSS, but we do not need to set it and removing it does
not make any change in the position of these elements.
So, this commit removes the pull-left class and its CSS
from bootstrap.css as well.

For the file type input, it is already hidden and after
removing the float property also, it is positioned at the
same place due to ordering of elements in HTML.

For the copy code button in codeblocks, it is postioned
using "position" and "right" attributes and removing
"float" property has no effect.

web/templates/compose_control_buttons.hbs

@@ -1,5 +1,5 @@
 <div class="compose_control_buttons_container order-1">
-    <input type="file" class="file_input notvisible pull-left" multiple />
+    <input type="file" class="file_input notvisible" multiple />
     {{#if file_upload_enabled }}
     <a role="button" class="compose_control_button compose_upload_file fa fa-paperclip notdisplayed" aria-label="{{t 'Upload files' }}" tabindex=0 data-tippy-content="{{t 'Upload files' }}"></a>
     {{/if}}

web/templates/copy_code_button.hbs

@@ -1,3 +1,3 @@
-<button class="btn pull-left copy_button_base copy_codeblock" data-tippy-content="{{t 'Copy code' }}" data-tippy-trigger="mouseenter" aria-label="{{t 'Copy code' }}">
+<button class="btn copy_button_base copy_codeblock" data-tippy-content="{{t 'Copy code' }}" data-tippy-trigger="mouseenter" aria-label="{{t 'Copy code' }}">
     {{> copy_to_clipboard_svg }}
 </button>

web/third/bootstrap/css/bootstrap.css

@@ -1343,9 +1343,6 @@ button.close {
   border: 0;
   -webkit-appearance: none;
 }
-.pull-left {
-  float: left;
-}
 .hide {
   display: none;
 }
@@ -1406,11 +1403,6 @@ button.close {
   }
 }
 @media (max-width: 480px) {
-  .media .pull-left {
-    float: none;
-    display: block;
-    margin-bottom: 10px;
-  }
   .modal {
     top: 10px;
     left: 10px;