[Jira] Fix false-positive "field name is duplicated" warnings when multiple boards share a connection

[bramhanandlingala]

closes: #9052

Summary
getIssueFieldMap() logged a "field name is duplicated" warning every time
a field name appeared more than once in _tool_jira_issue_fields, even when
it was the exact same field just present on multiple boards. On a
connection with several boards this produced hundreds of false-positive
warnings per pipeline run.

Root cause
_tool_jira_issue_fields stores one row per (connection_id, board_id, field
id), so a field present on N boards produces N rows with the same ID but
the same Name. getIssueFieldMap() warned on any second occurrence of a
Name without checking whether the ID actually differed, so board
recurrence was misread as a name collision.

Fix
Only warn when two different field IDs share the same display name, which
is the actual ambiguous case. The existing SchemaType == "user" override
is unchanged. Also fixed a typo in the log message: "filed name" -> "field
name".