ENG-56330 fixed empty seg and data class issues

[adityaKumar9006]

No description provided.

[jatin471]

@adityaKumar9006 in api naming, able to create empty segments URI Patterns

[jatin471]

In DC Overrides in span_filter/value_patterns operator Required is true but Value should be optional field as for EXIST operator value field is not required. And please add all operators (MATCHES_REGEX/EQUALS/EXISTS) in description

				"value_patterns": {
							Type:        schema.TypeList,
							Description: "Value operator and value",
							Optional:    true,
							MaxItems:    1,
							Elem: &schema.Resource{
								Schema: map[string]*schema.Schema{
									"operator": {
										Type:        schema.TypeString,
										Description: "Value operator  (MATCHES_REGEX/EQUALS)",
										Required:    true,
									},
									"value": {
										Type:     schema.TypeString,
										**Required: true,**
									},
								},
							},
						}