add self checks to issues and discussions templates (#1742)

.github/ISSUE_TEMPLATE/bug_report.yml

 labels:
 - bug
 body:
-- type: markdown
+- type: checkboxes
   attributes:
-    value: Please make sure to [search for existing issues](https://github.com/langgenius/dify/issues) before filing a new one!
+    label: Self Checks
+    description: "To make sure we get to you in time, please check the following :)"
+    options:
+      - label: I have searched for existing issues [search for existing issues](https://github.com/langgenius/dify/issues), including closed ones.
+        required: true
+      - label: I confirm that I am using English to file this report (我已阅读并同意 [Language Policy](https://github.com/langgenius/dify/issues/1542)).
+        required: true
+
 - type: input
   attributes:
     label: Dify version

.github/ISSUE_TEMPLATE/document_issue.yml

 labels: 
 - ducumentation
 body:
+- type: checkboxes
+  attributes:
+    label: Self Checks
+    description: "To make sure we get to you in time, please check the following :)"
+      - label: I confirm that I am using English to file this report (我已阅读并同意 [Language Policy](https://github.com/langgenius/dify/issues/1542)).
+        required: true
 - type: textarea
   attributes: 
     label: Provide a description of requested docs changes

.github/ISSUE_TEMPLATE/feature_request.yml

 labels:
 - enhancement
 body:
+- type: checkboxes
+  attributes:
+    label: Self Checks
+    description: "To make sure we get to you in time, please check the following :)"
+      - label: I confirm that I am using English to file this report (我已阅读并同意 [Language Policy](https://github.com/langgenius/dify/issues/1542)).
+        required: true
 - type: textarea
   attributes: 
     label: Description of the new feature / enhancement

.github/ISSUE_TEMPLATE/help_wanted.yml

 labels:
 - help-wanted
 body:
+- type: checkboxes
+  attributes:
+    label: Self Checks
+    description: "To make sure we get to you in time, please check the following :)"
+    options:
+      - label: I confirm that I am using English to file this report (我已阅读并同意 [Language Policy](https://github.com/langgenius/dify/issues/1542)).
+        required: true
 - type: textarea
   attributes:
     label: Provide a description of the help you need

.github/ISSUE_TEMPLATE/translation_issue.yml

 labels:
 - translation
 body:
-- type: markdown
+- type: checkboxes
   attributes:
-    value: Please make sure to [search for existing issues](https://github.com/langgenius/dify/issues) before filing a new one!
+    label: Self Checks
+    description: "To make sure we get to you in time, please check the following :)"
+    options:
+      - label: I have searched for existing issues [search for existing issues](https://github.com/langgenius/dify/issues), including closed ones.
+        required: true
+      - label: I confirm that I am using English to file this report (我已阅读并同意 [Language Policy](https://github.com/langgenius/dify/issues/1542)).
+        required: true
 - type: input
   attributes:
     label: Dify version