fix(Dr. Rai Report): Default goal to 0 (#5660)

**Story card:**
[sc-16474](https://app.shortcut.com/simpledotorg/story/16474/high-calculated-statement-activity-statement-is-shown-before-a-value-is-entered-in-the-input-the-initial-value-can-be-0)

## Because

UX upgrades

## This addresses

Showing the activity statement on empty state.

## Test instructions

1. Try adding an action plan
1. Check that the activity statement is 0 without an input in the input
box

Author: igbanam

app/components/dashboard/dr_rai_report.html.erb

@@ -94,7 +94,7 @@
             </label>
             <p class="missing-input-warning d-none">Enter a goal value</p>
           </div>
-          <p class="activity-promise d-none"><span class="active-action"></span> <span class="highlight target-number">500</span> <span class="indicator-unit"></span> by <%= end_of(selected_period) %></p>
+          <p class="activity-promise"><span class="active-action"></span> <span class="highlight target-number">0</span> <span class="indicator-unit"></span> by <%= end_of(selected_period) %></p>
           <p class="activity-statement"><span class="highlight"><span class="previous-percentage">6</span>%</span> <span class='indicator-action'></span> (<span class='indicator-previous-numerator'></span> of <span class='indicator-denominator'></span>) in <%= human_readable(selected_period.previous) %></p>
           <button class="next-button">Next</button>
         </div>
@@ -115,7 +115,7 @@
             </label>
             <p class="missing-input-warning d-none">Enter a goal value</p>
           </div>
-          <p class="activity-promise d-none"><span class="active-action"></span> <span class="highlight target-number">500</span> <span class="indicator-unit"></span> by <%= end_of(selected_period) %></p>
+          <p class="activity-promise"><span class="active-action"></span> <span class="highlight target-number">0</span> <span class="indicator-unit"></span> by <%= end_of(selected_period) %></p>
           <p class="activity-statement"><span class="highlight"><span class="indicator-previous-numerator">6</span></span> <span class='indicator-action'></span> (<span class='indicator-previous-numerator'></span> of <span class='indicator-denominator'></span>) in <%= human_readable(selected_period.previous) %></p>
           <button class="next-button">Next</button>
         </div>