Use project numbers in billing budget filter (#3555)

* Fixed project level billing budget filter

* Moved project_numbers local to concat block

* Fixed with try block

* fix project replacement

* tfdoc

* fix test

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Co-authored-by: Ludovico Magnocavallo <ludomagno@google.com>

modules/billing-account/variables.tf

@@ -130,6 +130,7 @@ variable "context" {
     project_ids           = optional(map(string), {})
     project_sets          = optional(map(list(string)), {})
     storage_buckets       = optional(map(string), {})
+    project_numbers       = optional(map(string), {})
   })
   default  = {}
   nullable = false