Tweak rendering of icons for accessibility (#31346)

* Tweak rendering of icons in dropdowns

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in composer format bar

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in jump to bottom button

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in quick settings button

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in left panel search

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Delint

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update snapshots

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Fix margin

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update test

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update snapshots

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in security user settings tab

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tweak rendering of icons in space hierarchy

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update screenshots

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Delint

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Simplify

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Tidy

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Add test

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update snapshots

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

res/css/components/views/elements/_FilterDropdown.pcss

@@ -40,7 +40,7 @@ Please see LICENSE files in the repository root for full details.
     }
 
     .mx_Dropdown_arrow {
-        background: $secondary-content;
+        color: $secondary-content;
     }
 }