Removed images and references to 'UI upgrades'

- Removed UCP UI images
- Removed reference to UCP UI Upgrades
- This commit also removed a lot of whitespace at the end of lines.

ee/ucp/admin/install/upgrade.md

@@ -77,7 +77,7 @@ with a new worker node. The type of upgrade you perform depends on what is neede
 
     - [Automated, in-place cluster upgrade](#automated-in-place-cluster-upgrade): Performed on any
     manager node. Automatically upgrades the entire cluster.
-    - Manual cluster upgrade: Performed using the CLI or the UCP UI. Automatically upgrades manager 
+    - Manual cluster upgrade: Performed using the CLI. Automatically upgrades manager
     nodes and allows you to control the upgrade order of worker nodes. This type of upgrade is more
     advanced than the automated, in-place cluster upgrade.
         - [Upgrade existing nodes in place](#upgrade-existing-nodes-in-place): Performed using the CLI.
@@ -125,7 +125,7 @@ of manager node upgrades.
 
 - [Automated, in-place cluster upgrade](#automated-in-place-cluster-upgrade): Performed on any
 manager node. Automatically upgrades the entire cluster.
-- Manual cluster upgrade: Performed using the CLI or the UCP UI. Automatically upgrades manager 
+- Manual cluster upgrade: Performed using the CLI. Automatically upgrades manager
 nodes and allows you to control the upgrade order of worker nodes. This type of upgrade is more
 advanced than the automated, in-place cluster upgrade.
     - [Upgrade existing nodes in place](#upgrade-existing-nodes-in-place): Performed using the CLI.