[FIX] web: oe-view-manager-content display issue on ie11

This tries to be the smallest patch possible in order to avoid triggering
another display issues, so we only patch in the ms-hight-contrast section
which only applies on ie 10/11.

* The view-manager weren't displayed correctly; they didn't fit 100% of
  the screen width. This is fixed by explicitely seting the top, right,
  left, bottom attributes.

* The modals content were not displayed. This was due to 2 issues:
  * The rule that we patch in the first point set the position of
    `oe-view-manager` as absolute with an importang flag. Because of
    this important, the rule that reset the position of the
    `oe-view-manager` as static in modals.less was not honored. So
    we also patch this rule with an important flag inside the same
    file (so that all the fixes related to ie10/11 are in the same
    place).
  * Now that the modals are displayed, they do not fit 100% of the
    screen. It's because the `max-height: 100%` of `.modal-content`
    set in modals.less does not work in ie10/11, due to some bug
    with the flex displays. We set the height to 450px so that the
    modals are kind of correctly displayed on a 1366x768 screen
    (their content are still scrollable).

related to rev 1ccd87a037
closes #12929

addons/web/static/src/css/base.css

@@ -3006,10 +3006,23 @@ body {
 @media screen and (-ms-high-contrast: active), (-ms-high-contrast: none) {
   .oe-view-manager-content > div {
     position: absolute !important;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
   }
   .oe-view-manager-content .oe-view-manager-content > div {
     position: relative !important;
   }
+
+  .modal .oe-view-manager-content > div {
+    position: static !important;
+    max-height: 450px;
+  }
+
+  .modal > .modal-dialog > .modal-content {
+    max-height: 450px;
+  }
 }
 .o_progressbar > div {
   display: inline-block;

addons/web/static/src/css/base.sass

@@ -2556,10 +2556,18 @@ body
     .oe-view-manager-content
         > div
             position: absolute !important
+            top: 0
+            right: 0
+            bottom: 0
+            left: 0
         .oe-view-manager-content
             > div
                 position: relative !important
-
+    .modal .oe-view-manager-content > div
+        position: static !important
+        max-height: 450px
+    .modal > .modal-dialog > .modal-content
+        max-height: 450px
 
 // au BufWritePost,FileWritePost *.sass :!sass --style expanded --line-numbers <afile> > "%:p:r.css"