mgr/dashboard: fix flaky RGW accounts and users e2e tests

accounts.po.ts: uncheck unlimited size before accessing bucket_quota_max_size
in edit() and invalidEdit(). The field is hidden by *ngIf when unlimited=true,
which is the default when an account is created without an explicit size.

users.e2e-spec.ts: replace UI-based account creation in the 'link user with
account' suite with a cy.request() API call in a before() hook. The old
approach called accounts.create() which made 5+ sequential RGW API calls and
exceeded Cypress's 120s timeout after 22 min of prior tests. account_id is now
stored via Cypress.env() instead of a JS variable, surviving test retries.

Signed-off-by: Afreen Misbah <afreen.misbah@ibm.com>

mgr/dashboard: fix RGW accounts edit and user-account link e2e tests

accounts.po.ts: uncheck accountunlimitedSize before accessing
account_quota_max_size in edit(). The field is hidden by *ngIf when
unlimited is checked (the default), same as the bucket quota section.

users.e2e-spec.ts: add the API version Accept header to the cy.request()
account creation in the 'link user with account' before() hook. Without
it the backend rejects the request with 415 (Unable to find version in
request header), skipping the whole suite.

Signed-off-by: Afreen Misbah <afreen.misbah@ibm.com>
Signed-off-by: Afreen Misbah <afreen@ibm.com>