Remove unused resolve button from HAML discussions

Currently Snippets and Commits still have HAML based discussions. Even
though one can use threads, they are not resolvable however.

The Vue counterpart of this code has been removed in more than a year
ago with 02ca0ed3

Also remove the icon_resolve_discussion and icon_status_success_solid
because it is their only usage.

app/views/projects/notes/_actions.html.haml

@@ -6,36 +6,6 @@
 - elsif note.contributor?
   %span{ class: 'note-role user-access-role has-tooltip', title: _("This user has previously committed to the %{name} project.") % { name: note.project_name } }= _("Contributor")
 
-- if note.resolvable?
-  - can_resolve = can?(current_user, :resolve_note, note)
-  %resolve-btn{ "project-path" => project_path(note.project),
-      "discussion-id" => note.discussion_id(@noteable),
-      ":note-id" => note.id,
-      ":resolved" => note.resolved?,
-      ":can-resolve" => can_resolve,
-      ":author-name" => "'#{j(note.author.name)}'",
-      "author-avatar" => note.author.avatar_url,
-      ":note-truncated" => "'#{j(truncate(note.note, length: 17))}'",
-      ":resolved-by" => "'#{j(note.resolved_by.try(:name))}'",
-      "v-show" => "#{can_resolve || note.resolved?}",
-      "inline-template" => true,
-      "ref" => "note_#{note.id}" }
-
-    .note-actions-item
-      %button.note-action-button.line-resolve-btn{ type: "button",
-          class: ("is-disabled" unless can_resolve),
-          ":class" => "{ 'is-active': isResolved }",
-          ":aria-label" => "buttonText",
-          "@click" => "resolve",
-          ":title" => "buttonText",
-          ":ref" => "'button'" }
-
-        %div
-          %template{ 'v-if' => 'isResolved' }
-            = render 'shared/icons/icon_status_success_solid.svg'
-          %template{ 'v-else' => '' }
-            = render 'shared/icons/icon_resolve_discussion.svg'
-
 - if can?(current_user, :award_emoji, note)
   - if note.emoji_awardable?
     .note-actions-item

app/views/shared/icons/_icon_resolve_discussion.svg

-<svg width="14" height="14" viewBox="0 0 14 14" xmlns="http://www.w3.org/2000/svg"><path d="M0 7a7 7 0 1 1 14 0A7 7 0 0 1 0 7z M13 7A6 6 0 1 0 1 7a6 6 0 0 0 12 0z" fill-rule="evenodd"/><path d="M6.278 7.697L5.045 6.464a.296.296 0 0 0-.42-.002l-.613.614a.298.298 0 0 0 .002.42l1.91 1.909a.5.5 0 0 0 .703.005l.265-.265L9.997 6.04a.291.291 0 0 0-.009-.408l-.614-.614a.29.29 0 0 0-.408-.009L6.278 7.697z"/></svg>

app/views/shared/icons/_icon_status_success_solid.svg

-<svg width="14" height="14" viewBox="0 0 14 14" xmlns="http://www.w3.org/2000/svg"><path d="M0 7a7 7 0 1 1 14 0A7 7 0 0 1 0 7z M6.278 7.697L5.045 6.464a.296.296 0 0 0-.42-.002l-.613.614a.298.298 0 0 0 .002.42l1.91 1.909a.5.5 0 0 0 .703.005l.265-.265L9.997 6.04a.291.291 0 0 0-.009-.408l-.614-.614a.29.29 0 0 0-.408-.009L6.278 7.697z" fill-rule="evenodd"/></svg>