chore(nimbus): Add Firefox 133.0b8 for targeting (#11759)

Because:

- we want to target Firefox 133 beta 8 specifically

This commit:

- adds a version for Firefox 133 beta 8

Fixes #11758

experimenter/experimenter/experiments/constants.py

@@ -581,6 +581,7 @@ class NimbusConstants:
         FIREFOX_132 = "132.!"
         FIREFOX_132_B6 = "132.0b6"
         FIREFOX_133 = "133.!"
+        FIREFOX_133_B8 = "133.0b8"
         FIREFOX_134 = "134.!"
         FIREFOX_135 = "135.!"
         FIREFOX_136 = "136.!"

experimenter/experimenter/nimbus-ui/schema.graphql

@@ -294,6 +294,7 @@ enum NimbusExperimentFirefoxVersionEnum {
   FIREFOX_132
   FIREFOX_132_B6
   FIREFOX_133
+  FIREFOX_133_B8
   FIREFOX_134
   FIREFOX_135
   FIREFOX_136

experimenter/experimenter/nimbus-ui/src/types/globalTypes.ts

@@ -125,6 +125,7 @@ export enum NimbusExperimentFirefoxVersionEnum {
   FIREFOX_132 = "FIREFOX_132",
   FIREFOX_132_B6 = "FIREFOX_132_B6",
   FIREFOX_133 = "FIREFOX_133",
+  FIREFOX_133_B8 = "FIREFOX_133_B8",
   FIREFOX_134 = "FIREFOX_134",
   FIREFOX_135 = "FIREFOX_135",
   FIREFOX_136 = "FIREFOX_136",