minor #43440 Add missing translation for Estonian (hluup)

This PR was merged into the 4.4 branch.

Discussion
----------

Add missing translation for Estonian

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #43431
| License       | MIT
| Doc PR        | N/A

Commits
-------

d668687ab3 Add missing translation for Estonian

Author: fabpot

Resources/translations/validators.et.xlf

@@ -390,6 +390,10 @@
                 <source>This value should be a valid expression.</source>
                 <target>See väärtus pole korrektne avaldis.</target>
             </trans-unit>
+            <trans-unit id="101">
+                <source>This value is not a valid CSS color.</source>
+                <target>See väärtus pole korrektne CSS-i värv.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>