fix typo in Yamato config. (#5176)

.yamato/com.unity.ml-agents-optional-dep-tests.yml

     dependencies:
         - .yamato/com.unity.ml-agents-pack.yml#pack
         {% for coverage_editor in coverage_test_editors %}
-        {% for coverage_plathform in coverage_test_platforms %}
+        {% for coverage_platform in coverage_test_platforms %}
         {% for coverage_package in coverage_test_packages %}
         - .yamato/com.unity.ml-agents-coverage.yml#test_coverage_{{ coverage_package.name }}_{{ coverage_platform.name }}_{{ coverage_editor.version }}
         {% endfor %}

.yamato/com.unity.ml-agents-test.yml

     name: Run All Combinations of Editors/Platforms Tests
     dependencies:
         {% for coverage_editor in coverage_test_editors %}
-        {% for coverage_plathform in coverage_test_platforms %}
+        {% for coverage_platform in coverage_test_platforms %}
         {% for coverage_package in coverage_test_packages %}
         - .yamato/com.unity.ml-agents-coverage.yml#test_coverage_{{ coverage_package.name }}_{{ coverage_platform.name }}_{{ coverage_editor.version }}
         {% endfor %}
     dependencies:
         - .yamato/com.unity.ml-agents-pack.yml#pack
         {% for coverage_editor in coverage_test_editors %}
-        {% for coverage_plathform in coverage_test_platforms %}
+        {% for coverage_platform in coverage_test_platforms %}
         {% for coverage_package in coverage_test_packages %}
         - .yamato/com.unity.ml-agents-coverage.yml#test_coverage_{{ coverage_package.name }}_{{ coverage_platform.name }}_{{ coverage_editor.version }}
         {% endfor %}
     dependencies:
         - .yamato/com.unity.ml-agents-pack.yml#pack
         {% for coverage_editor in coverage_test_editors %}
-        {% for coverage_plathform in coverage_test_platforms %}
+        {% for coverage_platform in coverage_test_platforms %}
         {% for coverage_package in coverage_test_packages %}
         - .yamato/com.unity.ml-agents-coverage.yml#test_coverage_{{ coverage_package.name }}_{{ coverage_platform.name }}_{{ coverage_editor.version }}
         {% endfor %}