Short answer: In the context of TB screening, Tier 5 visa holders are generally not considered as a "returning UK resident".
If the OP has been in the UK for at least six months, they should be exempted from Tuberculosis screening under a separate provision though.
Long answer:
What does the immigration rule says regarding Tuberculosis screening?
Paragraphs A39, B39, and C39 of the immigration rules states the following on Tuberculosis screening (text irrelevant to the OP's case removed, emphasis mine):
A39. Any person making an application for entry clearance to come to the UK for more than six months [...], having been present in a country listed in Appendix T for more than six months immediately prior to their application, must present, at the time of application, a valid medical certificate issued by a medical practitioner approved by the Secretary of State for these purposes, as listed on the Gov.uk website, confirming that they have undergone screening for active pulmonary tuberculosis and that this tuberculosis is not present in the applicant.
B39. Applicants seeking leave to enter as a returning resident under paragraph 19 of these rules, having been absent from the United Kingdom for more than two years are also subject to the requirements in paragraph A39.
C39. [...]
Hence "returning UK resident" listed on the GOV.UK page actually refers to "returning resident", a more restrictive term used by UKVI.
PBS Visa Holders are unlikely to be "returning residents"
The Government provided a guidance that defines who are returning residents under paragraph 19 (and 18) of the immigration rules. Page 10 gives a few non-examples:
The following do not qualify as returning residents:
- a person whose previous stay was subject to a time limit (for example a person
had limited leave to enter or remain)
Given almost all PBS visas comes with a time limit, it is unlikely that the OP qualifies as a returning resident.
Does the OP need to book a Tuberculosis screening then?
It depends on how long they have been in the UK on their Tier 5 visa.
Paragraph C39 of the immigration rules gives exemption to those who have been in the UK (and some other countries) for at least six months. The paragraph itself says:
C39. Where a person has lawfully been present in a country not mentioned in Appendix T for more than six months and they are applying for entry clearance as in A39 in a country in Appendix T but have not been in that country or any other country mentioned in Appendix T for more than six months immediately before making their application, they will not be required to produce a medical certificate showing they are free from active pulmonary TB. [...]
And in a more human-friendly version on GOV.UK:
You will not need a TB test if any of the following apply: [...]
- you lived for at least 6 months in a country where TB screening is not required by the UK, and you’ve been away from that country for no more than 6 months
