fix: bump realtime-js to 2.11.15

[grdsdev]

What kind of change does this PR introduce?

Close #1462

Additional context

Bug Fixes

• soft deprecation of headers and simplify ws socket connection (fix: soft deprecation of headers and simplify ws socket connection realtime-js#494) (7123690)
• resolve 'ws' peer dependency (fix: resolve 'ws' peer dependency realtime-js#495) (a9c0955)

[coveralls]

Pull Request Test Coverage Report for Build 15874278845

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 72.889%

---

Totals
Change from base Build 15848907171:	0.0%
Covered Lines:	109
Relevant Lines:	132

---

💛 - Coveralls