OCT-2000: Menubar icon state colour update (#451)

## Description

## Definition of Done

1. [ ] If required, the desciption of your change is added to the [QA
changelog](https://www.notion.so/octantapp/Changelog-for-the-QA-d96fa3b411cf488bb1d8d9a598d88281)
2. [ ] Acceptance criteria are met.
3. [ ] PR is manually tested before the merge by developer(s).
    - [ ] Happy path is manually checked.
4. [ ] PR is manually tested by QA when their assistance is required
(1).
- [ ] Octant Areas & Test Cases are checked for impact and updated if
required (2).
5. [ ] Unit tests are added unless there is a reason to omit them.
6. [ ] Automated tests are added when required.
7. [ ] The code is merged.
8. [ ] Tech documentation is added / updated, reviewed and approved
(including mandatory approval by a code owner, should such exist for
changed files).
    - [ ] BE: Swagger documentation is updated.
9. [ ] When required by QA:
    - [ ] Deployed to the relevant environment.
    - [ ] Passed system tests.

---

(1) Developer(s) in coordination with QA decide whether it's required.
For small tickets introducing small changes QA assistance is most
probably not required.

(2) [Octant Areas & Test
Cases](https://docs.google.com/spreadsheets/d/1cRe6dxuKJV3a4ZskAwWEPvrFkQm6rEfyUCYwLTYw_Cc).

client/src/components/shared/Layout/LayoutTopBar/LayoutTopBar.module.scss

@@ -150,7 +150,7 @@
     position: relative;
     &:hover {
       .allocateButtonIcon path {
-        stroke: $color-octant-grey5;
+        stroke: $color-octant-grey13;
       }
     }
 
@@ -164,7 +164,7 @@
       margin-left: 0.3rem;
 
       path {
-        stroke: $color-octant-grey2;
+        stroke: $color-octant-dark;
       }
     }
 
@@ -188,7 +188,7 @@
   .settingsButton {
     &:hover {
       .settingsButtonIcon path {
-        stroke: $color-octant-grey5;
+        stroke: $color-octant-grey13;
       }
     }
 
@@ -200,7 +200,7 @@
 
     .settingsButtonIcon {
       path {
-        stroke: $color-octant-grey2;
+        stroke: $color-octant-dark;
       }
     }
   }

client/src/styles/utils/_colors.scss

@@ -17,7 +17,7 @@ $color-octant-grey9: #d7d7d7; // TODO OCT-1001 Remove this color. It will become
 $color-octant-grey10: #323232;
 $color-octant-grey11: #777f78;
 $color-octant-grey12: #d8d8d8;
-$color-octant-grey13: #6B6B6B;
+$color-octant-grey13: #6b6b6b;
 $color-octant-green: #2d9b87;
 $color-octant-green-15: rgba(45, 155, 135, 0.15); // used in the metrics chart, not documented
 $color-octant-green-50: rgba(45, 155, 135, 0.5); // used in the metrics chart, not documented