Reduce number of buckets for open tabs daily pixel (#3663)

Task/Issue URL:
https://app.asana.com/0/1206226850447395/1208866352354120/f
Tech Design URL:
CC:

**Description**:

Reduces the temporary high granularity of opened tabs buckets.

**Steps to test this PR**:
1. Verify the validity of unit tests for daily open tabs pixel and
whether they pass.

**Definition of Done (Internal Only)**:

* [ ] Does this PR satisfy our [Definition of
Done](https://app.asana.com/0/1202500774821704/1207634633537039/f)?

---
###### Internal references:
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)

DuckDuckGo/TabSwitcherOpenDailyPixel.swift

@@ -49,12 +49,7 @@ struct TabSwitcherOpenDailyPixel {
         case 21...40: return "21-40"
         case 41...60: return "41-60"
         case 61...80: return "61-80"
-        case 81...100: return "81-100"
-        case 101...125: return "101-125"
-        case 126...150: return "126-150"
-        case 151...250: return "151-250"
-        case 251...500: return "251-500"
-        default: return "501+"
+        default: return "81+"
         }
 
     }

DuckDuckGoTests/TabSwitcherOpenDailyPixelTests.swift

@@ -51,12 +51,8 @@ final class TabSwitcherOpenDailyPixelTests: XCTestCase {
             21...40: "21-40",
             41...60: "41-60",
             61...80: "61-80",
-            81...100: "81-100",
-            101...125: "101-125",
-            126...150: "126-150",
-            151...250: "151-250",
-            251...500: "251-500",
-            501...504: "501+"]
+            81...90: "81+",
+            501...504: "81+"]
 
         for bucket in bucketValues {
             for value in bucket.key {