put reporter init after app startup

[NelsonVides]

Fixes MIM-1989

How to verify:

• Set a graphite node running, otherwise exometer_repert_graphite will crash.
• On a running node, execute in the shell exometer_report:list_subscriptions(exometer_report_graphite).
  • On master, we will not find totalSessionCount available
  • In this branch it is there, similarly for all the other missing metrics.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.02% ⚠️

Comparison is base (4433414) 83.90% compared to head (9b757d6) 83.89%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4085      +/-   ##
==========================================
- Coverage   83.90%   83.89%   -0.02%     
==========================================
  Files         527      527              
  Lines       33158    33158              
==========================================
- Hits        27822    27817       -5     
- Misses       5336     5341       +5     

Files Changed	Coverage Δ
src/metrics/mongoose_metrics.erl	92.92% <100.00%> (ø)

... and 10 files with indirect coverage changes

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[mongoose-im]

small_tests_24 / small_tests / 9b757d6
Reports root / small

---

elasticsearch_and_cassandra_25 / elasticsearch_and_cassandra_mnesia / 9b757d6
Reports root/ big
OK: 369 / Failed: 0 / User-skipped: 38 / Auto-skipped: 0

---

small_tests_25 / small_tests / 9b757d6
Reports root / small

---

small_tests_25_arm64 / small_tests / 9b757d6
Reports root / small

---

ldap_mnesia_24 / ldap_mnesia / 9b757d6
Reports root/ big
OK: 2258 / Failed: 0 / User-skipped: 827 / Auto-skipped: 0

---

dynamic_domains_pgsql_mnesia_24 / pgsql_mnesia / 9b757d6
Reports root/ big
OK: 4221 / Failed: 0 / User-skipped: 82 / Auto-skipped: 0

---

ldap_mnesia_25 / ldap_mnesia / 9b757d6
Reports root/ big
OK: 2258 / Failed: 0 / User-skipped: 827 / Auto-skipped: 0

---

dynamic_domains_mysql_redis_25 / mysql_redis / 9b757d6
Reports root/ big
OK: 4195 / Failed: 0 / User-skipped: 108 / Auto-skipped: 0

---

pgsql_mnesia_24 / pgsql_mnesia / 9b757d6
Reports root/ big
OK: 4604 / Failed: 0 / User-skipped: 89 / Auto-skipped: 0

---

dynamic_domains_pgsql_mnesia_25 / pgsql_mnesia / 9b757d6
Reports root/ big
OK: 4221 / Failed: 0 / User-skipped: 82 / Auto-skipped: 0

---

dynamic_domains_mssql_mnesia_25 / odbc_mssql_mnesia / 9b757d6
Reports root/ big
OK: 4218 / Failed: 0 / User-skipped: 85 / Auto-skipped: 0

---

mysql_redis_25 / mysql_redis / 9b757d6
Reports root/ big
OK: 4590 / Failed: 0 / User-skipped: 103 / Auto-skipped: 0

---

pgsql_mnesia_25 / pgsql_mnesia / 9b757d6
Reports root/ big
OK: 4604 / Failed: 0 / User-skipped: 89 / Auto-skipped: 0

---

internal_mnesia_25 / internal_mnesia / 9b757d6
Reports root/ big
OK: 2404 / Failed: 0 / User-skipped: 681 / Auto-skipped: 0

---

mssql_mnesia_25 / odbc_mssql_mnesia / 9b757d6
Reports root/ big
OK: 4601 / Failed: 0 / User-skipped: 92 / Auto-skipped: 0

[chrzaszcz]

Looks good, thanks for fixing this 👍