Issue #123: Fix schema issues in report_customsql_categories

[jnlar]

Resolves issue: https://github.com/moodleou/moodle-report_customsql/issues/123

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report_customsql_categories
 * column 'name' should be NOT NULL (C)
 * column 'name' has default 'Miscellaneous', expected 'NULL' (C)
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Added upgrade block that:

• Changes nullability of field name on table report_customsql_categories to not null
• Changes the default of field name on table report_customsql_categories to drop it.

[timhunt]

Sorry for not looking for this for so long.

However, not helpful to have a branches of 20+ commits that claims to just fix one bug.

Please rebase on latest main branch and I will take a look.