[PBNTR-462] Adding default value prop to Rails Star Rating kit (#3629)

**What does this PR do?**
Adding default value prop to Rails Star Rating kit


![image](https://github.com/user-attachments/assets/1d8699c8-6cfb-4b0e-ae31-e138bcc732ab)

**How to test?** Steps to confirm the desired behavior:
1. Go to the Rails Star Rating kit page.

#### Checklist:
- [x] **LABELS** Add a label: `enhancement`, `bug`, `improvement`, `new
kit`, `deprecated`, or `breaking`. See [Changelog &
Labels](https://github.com/powerhome/playbook/wiki/Changelog-&-Labels)
for details.
- [x] **DEPLOY** I have added the `milano` label to show I'm ready for a
review.
- [ ] **TESTS** I have added test coverage to my code.

playbook/app/pb_kits/playbook/pb_star_rating/docs/_star_rating_default_value.html.erb

@@ -0,0 +1 @@
+<%= pb_rails("star_rating", props: { default_value: "2", padding_bottom: "xs", variant: "interactive" }) %>

playbook/app/pb_kits/playbook/pb_star_rating/docs/example.yml

@@ -7,6 +7,7 @@ examples:
     - star_rating_number_config: Number Config
     - star_rating_size_options: Size Options
     - star_rating_interactive: Interactive
+    - star_rating_default_value: Default Value
 
   react:
     - star_rating_default: Default

playbook/app/pb_kits/playbook/pb_star_rating/index.js

@@ -12,6 +12,7 @@ export default class PbStarRating extends PbEnhancedElement {
   connect() {
     this.addEventListeners()
     this.handleFormReset()
+    this.setDefaultValue()
   }
 
   addEventListeners() {
@@ -128,7 +129,7 @@ export default class PbStarRating extends PbEnhancedElement {
     const form = this.element.closest("form")
     if (form) {
       form.addEventListener("reset", () => {
-        this.updateHiddenInputValue("")
+        this.element.querySelector(STAR_RATING_INPUT_DATA_SELECTOR)?.setAttribute("value","")
         this.resetStarRatingValues()
       })
     }
@@ -153,4 +154,13 @@ export default class PbStarRating extends PbEnhancedElement {
       }
     }
   }
+
+  setDefaultValue() {
+    const hiddenInput = this.element.querySelector(STAR_RATING_INPUT_DATA_SELECTOR)
+    const defaultValue = hiddenInput.value
+
+    if (defaultValue) {
+      this.updateStarColors(defaultValue)
+    }
+  }
 }

playbook/app/pb_kits/playbook/pb_star_rating/star_rating.rb

@@ -34,6 +34,7 @@ class StarRating < Playbook::KitBase
                       default: false
       prop :input_options, type: Playbook::Props::HashProp,
                            default: {}
+      prop :default_value
 
       def one_decimal_rating
         rating.to_f.round(1)
@@ -120,7 +121,8 @@ def all_input_options
           data: { "pb-star-rating-input": true },
           name: name,
           required: required,
-          style: "display: none"
+          style: "display: none",
+          value: default_value || ""
         )
       end
     end